CN102163432B

CN102163432B - Multilayer hard magnet and data storage device read/write head incorporating the same

Info

Publication number: CN102163432B
Application number: CN201010537767.XA
Authority: CN
Inventors: H·袁; 邱教明; Y·陈
Original assignee: Seagate Technology LLC
Current assignee: Seagate Technology LLC
Priority date: 2009-10-28
Filing date: 2010-10-27
Publication date: 2015-07-15
Anticipated expiration: 2030-10-27
Also published as: CN102163432A; JP2011096356A; JP5969974B2; JP2014063564A

Abstract

A hard magnet may include a seed layer including a first component including at least one of a Pt-group metal, Fe, Mn, Ir, and Co, a cap layer comprising the first component, and a multilayer stack between the seed layer and the cap layer. In some embodiments, the multilayer stack may include a first layer of including the first component and a second component including at least one of a Pt-group metal, Fe, Mn, Ir, and Co, where the second component is different from the first component. The multilayer stack may further include a second layer formed over the first layer and including the second component, and a third layer formed over the second layer and including the first component and the second component.

Description

Multilayer hard magnetic body and comprise the data storage device read-write head of multilayer hard magnetic body

The application is the U.S. Patent application S/N.12/112 submitted on April 30th, 2008, and the part continuation application of 671, its full content is included in by reference in this.

Background technology

Magnetic data storage device comprises the magnetic read-write head of the magnetic characteristic detecting and revise magnetic storage medium.Such as, read-write head comprises the magnetoresistive transducer changing impedance in response to applied magnetic field.Based on this change of impedance, the magnetic characteristic of read-write head sensing or amendment magnetic storage medium.

Summary of the invention

In an aspect, the present invention openly relates to a kind of hard magnetic body, and it comprises: the inculating crystal layer comprising the first composition, and wherein the first composition comprises at least one in Pt race metal, Fe, Mn, Ir and Co; Comprise the coating of the first composition; And multilayer laminated between inculating crystal layer and coating.According to this aspect disclosed by the invention, multilayer laminatedly to comprise: the ground floor comprising the first composition and the second composition, first composition and the second composition comprise at least one in Pt race metal, Fe, Mn, Ir and Co, and wherein the second composition is different from the first composition.Multilayer laminated also can comprising to be formed on ground floor and to comprise the second layer of the second composition, and to be formed on the second layer and to comprise the third layer of the first composition and the second composition.

Illustrate one or more embodiments of the detail of the present invention in the accompanying drawings and the description below.By reading detailed description below, these and other feature and advantage various will be apparent.

Accompanying drawing is sketched

Fig. 1 is the schematic diagram of hard disk drive.

Fig. 2 is the block diagram that the hard disk reading magnetic head comprising tunnel magneto sensor is shown.

Fig. 3 is the block diagram that hard disk reading magnetic head is shown.

Fig. 4 is the block diagram that another hard disk reading magnetic head is shown.

Fig. 5 is the phasor of platinum-iron binary system.

Fig. 6 is L1 ₀the structure cell of the platinum-iron bianry alloy of phase structure.

Fig. 7 is the block diagram of the sandwich construction comprising inculating crystal layer, coating and intermediate alloy layer.

Fig. 8 A-D is formed as single thin layer respectively, is formed as having platinum inculating crystal layer, is formed as having platinum coating and be formed as having the iron-magnetic moment of platinum magnetic material and the graph of relation in magnetic field of platinum inculating crystal layer and platinum coating.

Fig. 9 A-9C is the magnetic moment of iron-platinum alloy and the graph of relation in magnetic field that are formed as having inculating crystal layer and the coating comprising one of silver or platinum.

Figure 10 A-10D is the magnetic moment of iron-platinum alloy and the graph of relation in magnetic field that are formed as having inculating crystal layer and the coating comprising one of iron or platinum.

Figure 11 A-11C is the magnetic moment of iron-platinum alloy and the graph of relation in magnetic field that are formed as the various components with platinum inculating crystal layer and coating.

Figure 12 A and 12B is transmission electron microscope (TEM) microphoto of the iron with platinum inculating crystal layer and the platinum coating-platinum magnetic material before and after annealing respectively.

Figure 13 A and 13B is the iron with platinum inculating crystal layer and the platinum coating-concentration of platinum magnetic material and the graph of relation of the degree of depth of annealing front and back respectively.

Figure 14 is the iron-magnetic moment of platinum magnetic material and the graph of relation in magnetic field that are formed as having platinum inculating crystal layer and platinum coating.

Figure 15 is the block diagram of the multilayer iron-platinum alloy comprising two layers with different component.

Figure 16 A and 16B is sectional view and the composition curve figure of exemplary multiple layer hard magnetic body.

Figure 17 A and 17B is sectional view and the composition curve figure of exemplary multiple layer hard magnetic body.

Figure 18 A and 18B is sectional view and the composition curve figure of exemplary multiple layer hard magnetic body.

Figure 18 C is the sectional view of exemplary read sensor.

Figure 19 A and 19B is sectional view and the composition curve figure of exemplary multiple layer hard magnetic body.

Figure 20 is the process flow diagram that the illustrative methods forming multilayer hard magnetic body is shown.

Figure 21 is the iron-magnetic moment of platinum hard magnetic body and the graph of relation in magnetic field.

Describe in detail

The present invention openly relates generally to for the magnetic material in data-storage applications.In certain embodiments, magnetic material can be used for the read-write head of magnetic data storage device.These magnetic materials can be formed by the alloy comprising such as platinum (Pt) and iron (Fe), and are formed by the process annealing of alloy, inculating crystal layer and coating.Magnetic material preferably includes L1 ₀phase structure, and there is desirable high-coercive force and large saturation magnetization.

In certain embodiments, magnetic material can be formed as multilayer hard magnetic body.Such as, multilayer hard magnetic body can comprise inculating crystal layer, coating and multilayer laminated between inculating crystal layer and coating.Multilayer laminatedly comprise at least two-layer, and these layers can comprise different component.Such as, multilayer laminatedly comprise the multiple layers causing compositional gradient, its can about with inculating crystal layer and the roughly equidistant and substantially parallel plane symmetry of coating, or its can about with inculating crystal layer and the roughly equidistant and substantially parallel plane of coating asymmetric.In certain embodiments, the multilayer laminated different piece that may be provided in magnet has the magnet of different magnetic moment.

But discussion of the present invention in the read-write head of disk drive as the use of the magnetic material of lift magnet, these magnetic materials are also useful in other application needing high-coercive force and relative little magnetocrystalline particle size.Such as, for magnetic medium, magnetic material described herein can be useful.

Fig. 1 illustrates exemplary magnetic disc drive 100, and it comprises read-write head according to an aspect of the present invention.Disk drive 100 comprises bottom 102 and top cover 104, as cross-section shown in.Bottom 102 and top cover 104 combine the shell 106 forming disk drive 100.Disk drive 100 also comprises one or more rotatable magnetic data dish 108.Data disks 108 is attached to axle 114, and axle is in order to about central shaft rotating disc 108.Record and reading magnetic head 112 adjacent with data disks 108.Actuator arm 110 supports record and reading magnetic head 112 communicates for each data disks 108.

Information storage is magnetic aligning position by data disks 108 on magnetic film.Read-write head 112 comprises record (write) magnetic head, and it generates the magnetic field being enough to the discrete domain of magnetic film on magnetization data dish 108.These discrete domain of each magnetic film represent data bit, and one of them magnetic aligning represents " 0 " and substantially contrary magnetic aligning represents " 1 ".Record and reading magnetic head 112 also comprise reading magnetic head, and it can detect the magnetic field of the discrete magnetic domain of magnetic film.

Fig. 2 is the schematic block diagram of the embodiment that the hard disk reading magnetic head 200 that can use together with the read-write head 112 in Fig. 1 is shown.Reading magnetic head 200 utilizes magnetic resistance to read data from the data disks of data disks 108 grade of such as Fig. 1.Although the accuracy of reading magnetic head 200 can change on a large scale, tunnel magneto reading magnetic head is using as an example of the reading magnetic head 200 of disclosed magnetic material wherein can be utilized to describe.But be appreciated that magnetic material described herein can be used for any read head 200, such as example, electric current is first-class perpendicular to the gmr head of plane, gmr.In addition, magnetic material can find purposes in other application many needing high-coercive force and/or large saturation magnetization.

Refer again to Fig. 1-2, the air bearing that reading magnetic head 200 creates in the rotation by data disks 108 is skimmed over the surface of data disks 108.Data disks 108 has multiple data track 228, and one of them magnetic track is shown in Figure 2.Data track 228 can be divided into multiple position.As shown in arrow 226, when dish 108 rotates, reading magnetic head 200 moves along data track 228, and when it is in sensor 218 times each positions through out-of-date readable data magnetic track 228.

Reading magnetic head 200 comprises the first screen layer 202 and secondary shielding layer 203, tunnel magneto sensor 218 and two hard magnetic bodies 204,205.First and second screen layers 202,203 reductions or substantially block outside magnetic field, such as example by the external magnetic field etc. of shock transducer 218 from the adjacent bit on data disks 108, thus improve the performance of sensor 218.Ideally, the first and second screen layers 202,203 allow the influence of magnetic field sensor 218 of the position immediately below comfortable sensor 218, and are read thus.Therefore, the physical size along with position continues to reduce, and screen layer also can continue to reduce to the spacing of screen layer.

Sensor 218 comprises multiple layer, comprises antiferromagnetic inculating crystal layer 214, pinning layer 212, key horizon 211, tunnel barriers 210, free layer 208 and coating 206.Inverse ferric magnetosphere 214 is electrically coupled to the first electrode 221, and coating 206 is electrically coupled to the second electrode 220.Pinning layer 212 to be formed on inverse ferric magnetosphere 214 and to be exchange-coupled to inverse ferric magnetosphere 214.The magnetic moment of pinning layer 212 is fixed on known direction by this exchange coupling.Similarly, the magnetic moment of pinning layer 212 is inducted substantially antiparallel magnetic field in key horizon.Pinning layer 212 forms synthetic anti-ferromagnet 213 together with key horizon 211.Pinning layer 212 and the respective magnetic moment of key horizon 211 rotate in (magnetic field such as, generated by the data bit be stored on data disks 108) under not allowing the magnetic field in range of interest.The magnetic moment of key horizon 211 and pinning layer 212 is generally oriented to the plane perpendicular to Fig. 2, and as shown in arrow tail 224 and arrow 225 the antiparallel plane of Fig. 2 (such as, pass in and out) each other.

Sensor 218 also comprises free layer 208, and it is not exchange-coupled to antiferromagnet.Therefore, the magnetic moment of free layer 208 rotates freely in interested scope under the impact in applied magnetic field.

Reading magnetic head 200 also comprises a pair bias magnet 204 and 205, and it produces the magnetic field being biased free layer 208 with the magnetic moment as shown in arrow 226 of the plane and mean level orientation that are parallel to figure.This being biased prevents the magnetic moment of free layer 208 from drifting about due to such as heat energy, and noise may be introduced in the data sensed by reading magnetic head 200 by this drift.But the biased enough little magnetic moment of free layer 208 that makes can change in response to applied magnetic field, is such as stored in the magnetic field etc. of the data bit on data disks 108.Sensor 218 is separated and electric isolution with bias magnet 204,205 by insulating material 222,223 respectively with electrode 220,221.

Tunnel barriers 210 is separated free layer 208 and key horizon 211.Quantum mechanical electron tunneling is there is in enough thin the making of tunnel barriers 210 between key horizon 211 and free layer 208.Electron tunneling is that electron spin is correlated with, thus makes the magnetic response of sensor 218 become the relative orientation of key horizon 211 and free layer 208 and the function of spin polarization.The probability that electron tunneling occurs when the magnetic moments parallel of key horizon 211 and free layer 208 is the highest, and the probability of generation electron tunneling is minimum when the magnetic moment antiparallel of key horizon 211 and free layer 208.Correspondingly, the electrical response of sensor 218 changes in applied magnetic field.Namely or enter plan or from plan direction out data bit on data disks 108 is magnetized on the direction perpendicular to Fig. 2 plane.Therefore, when sensor 218 in data bit through out-of-date, in response to the magnetic field produced by the position below sensor 218, the magnetic moment of free layer 208 or rotate into the plane or from the Plane Rotation of Fig. 2 out of Fig. 2, thus change the resistance of sensor 218.The value of the position sensed by sensor 218 (such as, or 1 or 0) therefore can be determined based on the electric current flowing to the second electrode 220 from the first electrode 221.

In order to increase the memory capacity of the magnetic data storage device such as such as disk drive, the size in the magnetic aligning territory (position) on data disks 108 is made into more and more less constantly, to produce higher packing density.Correspondingly, the size of reading magnetic head 200 is made into more and more less sustainably, and more specifically, screen layer can reduce to the spacing of screen layer, to make sensor 218 substantially isolated with the magnetic field of adjacent bit on data disks 108.Fig. 3 and Fig. 4 illustrate when screen layer to screen layer spacing reduce time contingent example complexity.

Fig. 3 illustrates the embodiment of reading magnetic head 300, and it comprises the first screen layer 302 and secondary shielding layer 303 of separating distance 301.Be similar to reading magnetic head 200, reading magnetic head 300 comprises sensor 318, first bias magnet 304 and the second bias magnet 305.For clarity, the layer of sensor 318 is not shown in Figure 3.First bias magnet 304 comprises multiple domain magnetization 322, and each territory has the direction of magnetization represented by arrow 324.First bias magnet 304 produces the magnetic field represented by magnetic flux line 320a and 320b (being referred to as " magnetic flux line 320 ").As shown in the figure, a part of magnetic flux line 320b is launched less than in the plane of magnet 304,305 and sensor 318, and contrary crossing with one of screen layer 302 and screen layer 303.These magnetic flux lines represent that produced by the first bias magnet 304, to the free layer of sensor 318 the biased amount not doing the magnetic field of contributing.But magnetic flux line 320a is through sensor 318.These parts in magnetic field at least partially (such as, magnetic flux line 320a is parallel to) in the horizontal direction to the free layer of sensor 318 on biasedly to make contributions.

Fig. 4 then illustrates reading magnetic head 400, and it comprises the spacing 401 of less screen layer to screen layer, and this can be used for reading the less domain magnetization on data disks 108.In the embodiment shown in fig. 4, the size of bias magnet 404,405 is shown as compared with Fig. 3 less, less also than in Fig. 3 of sensor 418.But this may not be all real in all embodiments.Such as, in certain embodiments, only the thickness of insulation course is made less, and bias magnet 404,405 and sensor 418 keep identical size.

No matter whether the size of bias magnet 404,405 and sensor 418 is less, screen layer all causes the major part in the magnetic field generated by bias magnet 404 to run into one of the first screen layer 402 or secondary shielding layer 403, represented by magnetic flux line 420b to the reduction of the spacing 401 of screen layer.The institute's increase part running into the magnetic field of one of screen layer 402,403 causes the magnetic field part that can be used for biased free layer less (not shown in Figure 4), represented by single magnetic flux line 420a.Due to this lower biased, the signal to noise ratio (S/N ratio) of sensor 418 may lower than the signal to noise ratio (S/N ratio) of sensor 318, and this is disadvantageous.

Fig. 3-4 illustrates another complexity that can occur in less reading magnetic head 400 situation.Such as, bias magnet 404 comprises the magnetocrystalline grain 422 less relative to the magnetocrystalline grain 322 of magnetic bias 304.Less magnetocrystalline grain 422 can cause the heat energy in system to cause the high probability of magnetic moment oneself reorientation (as indicated by arrow 426) of each crystal grain 422.The magnetic moment reorientation of each magnetocrystalline grain 422 can reduce the overall magnetic moment of bias magnet 404, and reduces magnetic moment in fact significantly along with the time.

Therefore, needs have compared with high saturation and coercitive bias magnet 404,405.Higher magnetization can increase the magnetic flux line useful for biased free layer of bias magnet 404,405, and higher coercivity can increase magnetized stability.This can be convenient to again the use of less sensor (such as, sensor 418) in the reading magnetic head 400 of hard disk drive (such as, disk drive 100) conversely.

Comprise iron and can provide relative high-coercive force and magnetic moment with the alloy of platinum group metal.Platinum group metal can be selected from such as, Pt, Pd, Ir, Rh and Ru, or their combination.Preferably include the platinum group metal of Pt, especially preferably Pt.

Alloy also can comprise other a small amount of elements, such as copper, gold, silver etc.But in order to provide high-coercive force and high magnetic moment, iron-platinum alloy should preferably include high anisotropy L1 ₀or the phase structure of face-centered tetragonal.

Such as, as shown in iron-platinum (FePt) binary phase diagraml of Fig. 5, L1 ₀phase structure can be solid solution, and it comprises about 35 atomic percents (at.%) and the platinum about between 57at.% (Pt), and remaining is then Fe and incidental impurities (such as, being less than the impurity of 1at.%).More preferably, Fig. 6 illustrates L1 ₀phase structure, wherein Pt atom 602 and Fe atom 604 sort (for the Pt of about 50at.% and the Fe of about 50at%, not comprising incidental impurities) with the atomic ratio of 1: 1 in alternating layer.

L1 ₀usually require that the relatively-high temperature of FCC disordered alloy (also referred to as Al phase alloy) (being greater than about 500 DEG C) is annealed to produce L1 mutually ₀the ordered structure of the Pt in phase structure and iron (Fe) atom.This high-temperature annealing step prevents the use of FePt alloy in such as reading magnetic head such as hard magnetic body such as reading magnetic head 200 grade, because the remaining component of reading magnetic head 200 (such as, sensor 218) is degenerated at these temperatures.

In one aspect, the present invention openly relates to and does not require high-temperature annealing step and form the method for alloy with ordered phase structure.The method generally comprises the sandwich construction using and comprise inculating crystal layer and coating.Sandwich construction also comprises at least one middle layer, and this middle layer comprises alloy.In certain embodiments, inculating crystal layer and/or coating comprise alloying component, and in some preferred embodiments, this inculating crystal layer and/or cladding compositions are the minority compositions of alloy.

Fig. 7 illustrates sandwich construction 700, and it can be used for producing the ordered phase structure alloy with high anisotropy.The middle layer 706 that sandwich construction 700 comprises inculating crystal layer 702, coating 704 and is formed between inculating crystal layer 702 and coating 704.Alloy-layer 706, inculating crystal layer 702 and coating 704 can be made up of various composition, and it comprises such as Pt, Fe, Mn, Ir, Co or other similar compositions for generation of ferrimag, ferrimag or antiferromagnetic alloy.In certain embodiments, inculating crystal layer 702 and coating 704 comprise the composition be present in alloy-layer 706.In other embodiments, inculating crystal layer 702 and coating 704 comprise the composition be not present in alloy-layer 706.

In certain embodiments, at least one in inculating crystal layer 702 and coating 704 comprises more than one compositions be present in alloy-layer 706.Such as, inculating crystal layer 702, coating 704 and alloy-layer 706 can each self-contained first and second compositions.In certain embodiments, one of at least comprise principal ingredient in inculating crystal layer 702 and coating 704, this principal ingredient is marginally present in alloy-layer 706.Such as, one of at least can comprise a large amount of Pt and a small amount of Fe in inculating crystal layer 702 and coating 704, wherein alloy-layer 706 comprises a large amount of Fe and a small amount of Pt.In certain embodiments, both inculating crystal layer 702 and coating 704 comprise principal ingredient, and this principal ingredient is marginally present in alloy-layer 706.

Inculating crystal layer 702, alloy-layer 706 and coating 704 can use many deposition techniques, comprise such as sputtering, ion beam depositing, chemical vapor deposition, physical vapour deposition (PVD), molecular beam epitaxy, laser ablation etc.In one embodiment, use one of these technology to be deposited on substrate by inculating crystal layer 702, use identical or different technologies to be deposited on inculating crystal layer 702 by alloy-layer 706, and use any technology of these technology to be deposited on alloy-layer 706 by coating 704.

Compared to the single film of annealed alloy, annealing, only there is the alloy of inculating crystal layer 702 or annealing only has the alloy of coating 704, utilize inculating crystal layer 702 and coating 704 to have superiority.Fig. 8 A-D illustrates this advantage.Shown in these curve maps one important parameter is the coercive force of alloy.Coercive force is that magnetic moment equals zero the magnetic field at place, or the point that magnetic moment-field curve is crossing with magnetic field axis (x-axis).The coercive force instruction atomic arrangement degree that becomes ordered phase to construct in face, and the degree of magnetic anisotropy in alloy.That is, higher interior coercive force indicates the alloy with the high-sequential more of larger magnetic anisotropy.

Such as, Fig. 8 A illustrates the magnetic moment of the FePt alloy in response to applied magnetic field.Before annealing, the FePt alloy of Fig. 8 A comprises the Pt of about 38at.% and the Fe of about 62at.%, and anneals at the temperature of about 300 DEG C about 4 hours.As shown in the figure, 1420Oe is roughly by the coercitive absolute value of curve 801 and 802 being averaging coercive force in the face that calculates.Fig. 8 B then illustrates the FePt alloy with the alloy of Fig. 8 A with same composition, and it is formed as having Pt inculating crystal layer 702.The sample that sample in Fig. 8 B is similar to Fig. 8 A is annealed 4 hours at the temperature of about 300 DEG C.The sample of Fig. 8 B illustrates, is approximately 2400Oe by the coercitive absolute value of curve 803 and 804 being averaging coercive force in the face that calculates.

Fig. 8 C comprises the result of the FePt alloy sample of the Pt of about 38at.% and the Fe of about 62at.% before annealing is shown again.This sample with Pt coating 704 is annealed 4 hours at the temperature of about 300 DEG C.This sample illustrates, by the alloy that is similar to Fig. 8 B the coercitive absolute value of curve 805 and 806 is averaging coercive force in the face calculated and is approximately 2200Oe.

Fig. 8 D comprises the result of the FePt alloy sample of the Pt of about 38at.% and the Fe of about 62at.% before annealing is then shown, this sample is formed as having Pt inculating crystal layer 702 and Pt coating 704, and anneals 4 hours at the temperature of about 300 DEG C.This sample illustrates, be approximately 5100Oe by the coercitive absolute value of curve 807 and 808 being averaging coercive force in the face that calculates, it is significantly higher than the coercive force of the arbitrary sample shown in Fig. 8 A-8C.Although do not wish that this effect of current available data representation is the phase counterdiffusion owing to occurring in inculating crystal layer 702/ alloy-layer 706 and coating 704/ alloy-layer 706 two interfaces, and it is convenient to Fe with Pt atomic order and becomes L1 by any theory constraint ₀phase structure.

In certain embodiments, inculating crystal layer 702 and coating 704 can comprise the composition be not present in alloy-layer 706.Such as, in one embodiment, inculating crystal layer 702 and/or coating 704 comprise silver, and alloy-layer 706 comprises FePt alloy.

Fig. 9 A-C illustrates the three kinds of magnetic moment of FePt alloy and graph of relation in magnetic field being formed as having different inculating crystal layer 702 and coating 704 component.As shown in Figure 9 A, to have silver-colored inculating crystal layer 702 and silver-colored coating 704, comprise the Pt of about 38at.% and the FePt alloy of the Fe of about 62at.% before annealing and at about 300 DEG C, carry out annealing in about 4 hours can produce coercitive FePt alloy in the relative bottom surface that has and be about 200Oe.Fig. 9 B illustrate identical with the component of Fig. 9 A, that be formed as having silver-colored inculating crystal layer 702 and platinum coating 704, anneal under the same conditions after the response of FePt alloy.In its face, coercive force is much higher, is about 1300Oe.Fig. 9 C then illustrate identical with the component of Fig. 9 A, that be formed as having platinum inculating crystal layer 702 and silver-colored coating 704, anneal under the same conditions after the response of FePt alloy.In the face of this sample, coercive force is about 2300Oe.These coercive forces are more much lower than the coercive force of sample shown in Fig. 8 D, and sample shown in Fig. 8 D is formed as having platinum inculating crystal layer 702 and platinum coating 704.

Inculating crystal layer 702 and coating 704 also can comprise the composition that a small amount of (that is, being less than 50at.%) is present in intermediate alloy layer 706, or also can comprise the composition that a large amount of (that is, more than 50at.%) is present in alloy-layer 706.In certain embodiments, the inculating crystal layer 702 comprising the composition be present on a small quantity in alloy-layer 706 and coating 704 is used to have superiority.Such as, comprise to produce the L1 that principal ingredient is Fe ₀fePt alloy, can use Pt inculating crystal layer 702 and Pt coating 704.As another example, comprise to produce the L1 that principal ingredient is Pt ₀fePt alloy, can use Fe inculating crystal layer 702 and Fe coating 704.

The use of the inculating crystal layer 702 and coating 704 that comprise the composition being present in intermediate alloy layer 706 on a small quantity can cause the composition in inculating crystal layer 702 and coating 704 to spread to alloy-layer 706, and other compositions (being present in the composition in alloy-layer 706 in a large number) spread from alloy-layer 706 to inculating crystal layer 702 and coating 704.The diffusion of these two kinds of compositions causes alloy to have the component closer to 50: 50 compared to initial alloy.The diffusion of these two kinds of compositions is also convenient to generation and is become L1 ₀the necessary atomic rearrangement sequence of phase transformation of phase.

Figure 10 A-D illustrates a series of samples after annealing about 4 hours at the temperature of about 300 DEG C, and before annealing, it comprises the Fe of about 36at.% and the Pt of about 64at.%.Figure 10 A illustrates and is formed as the magnetic moment of the sample with Pt inculating crystal layer 702 and Pt coating 704 and the graph of relation in magnetic field.This sample illustrates coercive force in bottom surface, the bad sequence of its instruction atom and less anisotropy.Figure 10 B illustrates the response being formed as the similar alloy with Pt inculating crystal layer 702 and Fe coating 704.In its face, coercive force is comparatively large, is about 700Oe, its instruction be formed as that there is Pt inculating crystal layer 702 and compare with the sample of coating 704, Fe and Pt atom is ranked into L1 better ₀phase structure.Figure 10 C is the response curve being formed as another similar alloy with Fe inculating crystal layer 702 and Pt coating 704.In its face, coercive force is about 600Oe, similar to the coercive force of sample shown in Figure 10 B.

Figure 10 D illustrates the response being formed as the alloy with Fe inculating crystal layer 702 and Fe coating 704.In its face, coercive force is higher significantly, is about 1500Oe, Fe and the Pt atom of its instruction alloy-layer 706 is ranked into L1 better ₀phase structure and higher anisotropy thereof.

Result shown in Fig. 9 A-9C and 10A-10D illustrates, plays an important role when the component of inculating crystal layer 702 and coating 704 forms orderly phase structure in alloy-layer 706, and this is indicated by the coercive force of alloy.Such as, Fig. 9 A-C means, when inculating crystal layer 702 and coating 704 comprise the composition of alloy-layer 706, annealing in process more effectively produces the ordered phase structure with high anisotropy in alloy-layer 706.Figure 10 A-D then illustrates, when inculating crystal layer 702 and coating 704 comprise the composition be present on a small quantity in alloy-layer 706, annealing in process is even more effective when producing the ordered phase structure with high-coercive force.

The use of inculating crystal layer 702 and coating 704 is intended to be convenient to be formed the ordered phase structure with high-coercive force.Although do not wish by any theory constraint, the composition that inculating crystal layer 702 and coating 704 can strengthen alloying component and inculating crystal layer 702, coating 704 is in the phase counterdiffusion of the interface of inculating crystal layer 702 and intermediate alloy layer 706 and the interface at coating 704 and alloy-layer 706.This in interface component through improving phase counterdiffusion, the sequence of whole alloy-layer 706 can be improved, also the better stoichiometric ratio of the component of alloy-layer 706 to component can be driven.This causes alloy to comprise having the ordered phase structure of high anisotropy, such as L1 ₀phase structure, L1 ₂phase structure etc.

Due to the phase counterdiffusion of enhancing provided by the use of inculating crystal layer 702 and coating 704, high-coercive force alloy can be formed under much lower annealing temperature.Such as, FePt L1 ₀alloy produces by carrying out the annealing of nearly 6 hours in about 250 DEG C to the temperature range of 400 DEG C to sandwich construction 700.Preferably, sandwich construction 700 at the temperature of about 250 DEG C to about 350 DEG C, can be annealed under being more preferably the temperature of 300 DEG C.In certain embodiments, annealing can preferably carry out about 4 hours.

Compared with annealing with higher temperature, lower temperature is annealed the crystal grain-growth that can limit in alloy.Such as, for be used for magnetic storage medium magnetic material this especially cater to the need, wherein packing density is relevant to the crystallite dimension of magnetic material.

Orderly and the anisotropic amount produced by process annealing, the coercive force of alloy also depends on the relative quantity of Fe and Pt in alloy-layer 706 thus.The magnetic moment of three kinds of alloy compositions after Figure 11 A-C illustrates and about anneals 4 hours at about 300 DEG C, there is Pt inculating crystal layer 702 and coating 704 and the graph of relation in magnetic field.Such as, Figure 11 A comprises the response of the alloy of the Fe of about 62at.% and the Pt of about 38at.% before annealing is shown.5100Oe is approximately, as shown in 8D by the coercitive absolute value of curve 1101 and 1102 being averaging coercive force in the face that calculates.Figure 11 B comprises the response of the alloy of the Fe of about 70at.% and the Pt of about 30at.% before annealing is shown.Be found to be about 4000Oe by the coercitive absolute value of curve 1103 and 1104 being averaging coercive force in the face that calculates.Finally, Figure 11 C comprises the response of the alloy of the Fe of about 77at.% and the Pt of about 23at.% before annealing is shown.Be found to be about 1200Oe by the coercitive absolute value of curve 1105 and 1106 being averaging coercive force in the face that calculates.These results illustrate that the coercive force of FePt alloy reduces along with the increase of Fe content.Although do not wish by any theory constraint, thinking that coercive force reduces is owing to becoming L1 ₀the degree of order of the FePt alloy of phase structure reduces.

Figure 12 A and 12B illustrates transmission electron microscope (TEM) microphoto of the Pt-FePt-Pt sandwich construction before and after annealing respectively.The bottom of Figure 12 A and the blanking bar at top place are Pt inculating crystal layer 1202a and coating 1204a respectively, and brighter middle layer 1206a is FePt alloy.After annealing at about 300 DEG C about 4 hours, become less obvious from Pt layer 1202b, 1204b to the transformation of middle layer 1206b, and the shading value of layer 1206 own is also more even, its hint is evenly the formation of phase structure.

Figure 13 A and 13B illustrates and is similar to the component of the sample shown in Figure 12 A and 12B and the exemplary graph of depth relationship.Figure 13 A illustrates at surface peace treaty pure Pt layer 1302a, 1304a of depth.From about arrive about zone line 1306a comprise alloy, this alloy comprises the Fe of about 60at.% and the Pt of about 40at.%.After annealing at the temperature of about 300 DEG C about 4 hours, remeasure sample and produce curve map as shown in Figure 13 B.As shown in the figure, Pt is from two pure Pt layers to FePt alloy diffusion.Correspondingly, the Pt content of layer 1302b and 1304b is down to about 95at.%, and the Pt content of FePt alloy zone line 1306b rises to about 45at.%.In addition, although not shown, phase structure becomes L1 from FCC ₀.

Figure 14 illustrates the magnetic response curve map of the FePt bianry alloy of the Pt of Fe and the about 36at.% comprising about 64at.%.This sample had been annealed about 4 hours before magnetic response is measured at the temperature of about 300 DEG C, and had been formed as having Pt inculating crystal layer and Pt coating.Alloy illustrate be about 9130Oe face in coercive force.

There is the L1 formed by said method ₀the FePt alloy of phase structure can be hard disk reading magnetic head and makes desirable bias magnet.L1 ₀fePt alloy has suitable high-coercive force and magnetic moment to be biased free layer in expectation magnetic aligning.In addition, in alloy, the relative quantity of Fe and Pt can be designed to provide desired characteristic to bias magnet.Such as, form the alloy with higher Fe content and cause comparatively high saturation, but cause comparatively low-coercivity.On the contrary, form the alloy with higher Pt content and cause lower saturated magnetization, but cause higher coercivity.

Before annealing, bias magnet can comprise from the Fe of the Pt of the Fe of about 80at.% and about 20at.% to about 30at.% and the Pt of about 70at.%, preferably includes from the Fe of the Pt of the Fe of about 65at.% and about 35at.% to about 40at.% and the Pt of about 60at.%.

FePt bias magnet can comprise the thickness of the geometric configuration depending on hard disk reading magnetic head at least in part.Such as, the screen layer of hard disk reading magnetic head of the present invention can be from about to the scope of screen layer distance arrive about correspondingly, the thickness of sandwich construction 700 can thickly reach about in some preferred embodiments, inculating crystal layer 702 and coating 704 comprise thick reaching about separately thickness, more preferably, thickness range is about arrive about intermediate alloy layer 706 can comprise thick reaching about thickness, be preferably about to being about

Bias magnet can be placed in reading magnetic head (such as, reading magnetic head 200) as the step of in reading magnetic head manufacture, and whole reading magnetic head is exposed to formation L1 subsequently ₀the necessary process annealing of phase structure.The low performance to being enough to the remainder (such as, sensor 218) not affecting reading magnetic head of annealing temperature.

L1 disclosed by the invention ₀the FePt alloy of phase structure also can comprise multiple layers of different component.Such as, alloy can comprise the layer being rich in Pt and the layer being rich in Fe.The multiple layers comprising different component can allow to customize the magnetic field produced by bias magnet further, thus introduce biased to the free layer of sensor and other layers.

Such as, in many embodiments, free layer has relatively high biased, and have on key horizon and pinning layer minimum biased may be desirable.For this reason, as shown in figure 15, bias magnet can comprise roughly adjacent to the layer 1506 being rich in Fe of free layer 1512, and roughly adjacent to the less layer 1504 being rich in Fe of tunnel barriers 1514, key horizon 1516 and/or pinning layer 1518.The layer 1506 being rich in Fe produces the fully large magnetic field that represented by magnetic flux line 1508 with biased free layer 1512; And the layer 1504 of the less Fe of being rich in has high-coercive force, but produce the relatively weak magnetic field represented by magnetic flux line 1510, thus do not affect key horizon 1516 and pinning layer 1518 consumingly.Bias magnet 1500 also comprises Pt inculating crystal layer 1502 and Pt coating 1520, its make as mentioned above the less Fe of being rich in layer 1504 and be rich in Fe layer 1506 in can form L1 ₀phase structure.

In addition, the method easily extensible of ordered phase structure alloy is produced in other materials alloy.Such as, the method for inculating crystal layer and coating is used to can be used for producing L1 ₀the CoPt alloy of phase structure, uses in the application of magnetic material needing high anisotropy.In addition, the method can be used for producing L1 ₂the IrMn used as antiferromagnet of phase structure ₃or PtMn ₃material.

As mentioned above, in certain embodiments, bias magnet can comprise the multiple layers (multilayer laminated) between inculating crystal layer and coating.This is multilayer laminated can provide one or more characteristic to bias magnet.Such as, in certain embodiments, comprise inculating crystal layer, coating and the multilayer laminated bias magnet between inculating crystal layer and coating can anneal at reduced temperatures to cause and become such as L1 ₀the phase transformation of the ordered phase of phase.In these embodiments, the component of each layer can be different, and between adjacent layer, the difference of component can cause one or more components of a layer to spread to adjacent layer, or just in time contrary.These diffusions can be convenient to ordered phase and be formed, and can reduce annealing temperature, and this can be used for producing ordered phase compared with comprising the bias magnet of single intermediate alloy layer.Such as, in certain embodiments, can be annealed to form ordered phase at the temperature of about 200 DEG C to about 500 DEG C by inculating crystal layer, coating and the multilayer laminated bias magnet formed between inculating crystal layer and coating.In other embodiments, bias magnet can the temperature of about 200 DEG C to about 300 DEG C, or be annealed to form ordered phase at the temperature of about 280 DEG C.In some instances, each layer can comprise alternately component, such as, be alternately rich in the layer of Pt and be rich in the layer of Fe.

In other examples, multilayer laminated layer can have the component causing bias magnet to have compositional gradient; That is, with the component of the one or more change in orientation in bias magnet.Comprise inculating crystal layer, coating and the multilayer laminated bias magnet between inculating crystal layer and coating and may be provided in magnetic moment and/or coercive force that at least one orientation of bias magnet changes.Magnetic moment and/or coercive force can be dependent on the component of bias magnet.Like this, the bias magnet had along with the component of one or more change in orientation can cause bias magnet to have magnetic moment along with one or more change in orientation and/or coercive force.Such as, have such as be rich in Pt to the bias magnet of the compositional gradient being rich in Fe can have magnetic moment gradient, coercive force gradient or both.

Figure 16 A illustrates example bias magnet 1600, and it can comprise inculating crystal layer 1602, coating 1612 and multilayer laminated 1604 between inculating crystal layer 1602 and coating 1612.In the embodiment shown in Figure 16 A and 16B, multilayer laminated 1604 comprise ground floor 1606, the second layer 1608 and third layer 1610.In other embodiments, multilayer laminated 1604 can comprise more or less layer.

Usually, inculating crystal layer 1602 and coating 1612 can comprise above-mentioned at least one composition.Such as, inculating crystal layer 1602 and/or coating 1612 can comprise at least one of Pt race metal, Fe, Mn, Ir, Co etc.Pt race metal can comprise at least one in Pt, Pd, Ir, Rh and Ru.In certain embodiments, at least two kinds of alloys that one of at least can comprise Fe, Mn, Ir, Co, Pt race metal etc. in inculating crystal layer 1602 and coating 1612.Inculating crystal layer 1602 and coating 1612 can comprise identical component, or inculating crystal layer 1602 and coating 1612 can comprise heterogeneity.

Similarly, ground floor 1606, the second layer 1608 and third layer 1610 can comprise at least one of Pt race metal, Fe, Mn, Ir, Co etc. separately.In certain embodiments, the alloy that one of at least can comprise at least two kinds of compositions of ground floor 1606, the second layer 1608 and third layer 1610.Every one deck of ground floor 1606, the second layer 1608 and third layer 1610 can comprise the alloy of identical component, the alloy of identical component, heterogeneity or heterogeneity.In certain embodiments, ground floor 1606, the second layer 1608 and third layer 1610 comprise similar component, and ground floor 1606, the second layer 1608 and third layer 1610 one of at least comprise at least another layer of different component (such as, the different proportion of identical component) from ground floor 1606, the second layer 1608 and third layer 1610.

Figure 16 B is the composition curve figure of an example of bias magnet 1600, and it extends to the component of the Fe of 100at.% from the component of the Pt of 100at.%.The example component of the bias magnet 1600 of (line 1614,1616,1618,1620 and 1622) and annealing rear (line 1624) before Figure 16 B illustrates annealing.As shown in fig 16b, inculating crystal layer 1602 and coating 1612 can comprise separately as the Pt close to 100at.% respectively represented by line 1614 and 1622.Although Figure 16 B is not shown, inculating crystal layer 1602 and/or coating 1612 can comprise other compositions that are except Pt or alternative Pt.In addition, in certain embodiments, inculating crystal layer 1602 can comprise the component being different from coating 1612.

Be back to Figure 16 B, ground floor 1606 and third layer 1610 can comprise the Fe than inculating crystal layer 1602 and coating more than 1612, respectively represented by line 1616 and line 1620.In other embodiments, ground floor 1606 and third layer 1610 can comprise with the alloy phase represented by line 1616 and line 1620 than being rich in the more alloy of Fe or being rich in the less alloy of Fe.The second layer 1608 can comprise the Fe of maximum, as shown in line 1618.And the alloy of Pt and Fe is comprised according to Figure 16 B second layer 1608, in other embodiments, the second layer only can comprise Fe or is rich in the more alloy of Fe with the alloy phase represented by Figure 16 B than comprising or is rich in the more alloy of Fe.As shown in figure 16 a and 16b, bias magnet 1600 has and all substantially distributes about with the component of inculating crystal layer 1602 and roughly equidistant and substantially parallel plane 1634 symmetry of coating 1612 before and after annealing.

As shown in line 1624, compared to the component distribution before annealing, the annealing of bias magnet 1600 can cause the distribution of its component fuzzy or level and smooth.As shown in line 1624, the composition of each layer 1602,1606,1608,1610 and 1612 can spread between the adjacent layer of bias magnet at During Annealing.Such as, a part of Fe in ground floor 1606 can diffuse to inculating crystal layer 1602, and can diffuse to ground floor 1606 from the Pt of inculating crystal layer 1602.Similar diffusion also can occur between other adjacent layers, such as, between ground floor 1606 and the second layer 1608, between the second layer 1608 and third layer 1610, and between third layer 1610 and coating 1612.Between the adjacent layer of bias magnet 1600, the diffusion of composition can cause more level and smooth or fuzzyyer compositional gradient, and the atomic order can being convenient to layer becomes orderly crystal structure, such as L1 ₀phase structure etc.Although Figure 16 B annealing is shown after compositional gradient (line 1624), it comprise rounded step and and non-fully is level and smooth, in other embodiments, component distribution can be more level and smooth or more unsmooth.Specific components distribution after annealing can be the function of multiple parameter, and these parameters for example comprise annealing time, annealing temperature, the thickness of layer 1602,1606,1608,1610 and 1612, the component etc. of layer 1602,1606,1608,1610 and 1612.The present invention is open it is conceivable that more level and smooth and more rough other components distribution in any case.

As mentioned above, the bias magnet 1600 comprising higher Fe number percent can have higher moment and comparatively low-coercivity compared to the bias magnet comprising lower Fe number percent.Similarly, the layer comprising higher Fe number percent has higher moment and comparatively low-coercivity compared to the layer comprising lower Fe number percent.Like this, compared with ground floor 1606, third layer 1610, inculating crystal layer 1602 and coating 1612, the second layer 1608 can have higher moment and comparatively low-coercivity.In certain embodiments, the second layer 1608 can with the free layer of read sensor, such as free layer 226 (Fig. 2) roughly aligns, and inculating crystal layer 1602, ground floor 1606, third layer 1610 and coating 1612 can adjacent to other layers of sensor, other layers (Fig. 2) of such as sensor 218.In such as these embodiment, affect the layer of sensor 218 but not the intensity in the magnetic field of free layer 226 can reduce, this can improve the reading performance of sensor 218.Such as, the described alignment of bias magnet 1600 and sensor 218 can improve the signal to noise ratio (S/N ratio) of sensor.

Inculating crystal layer 1602 and coating 1612 can comprise thick reaching about separately thickness, more preferably, thickness range is about arrive about multilayer laminated 1604 can comprise thick reaching about gross thickness, and it is about in certain embodiments extremely about ground floor 1606, the second layer 1608 and third layer 1610 can have comparable thickness or different-thickness.Every one deck of ground floor 1606, the second layer 1608 and third layer 1610 can comprise thick reaching about thickness, and can to have about in certain embodiments extremely thickness, or about extremely thickness.

Inculating crystal layer 1602, ground floor 1606, the second layer 1608, third layer 1610 and coating 1612 can use, such as, and the formation such as sputtering, ion beam depositing, chemical vapor deposition, physical vapour deposition (PVD), molecular beam epitaxy, laser ablation.Each layer can use identical technology to be formed, or at least one layer of these layers is formed by the technology that at least one other layer from these layers is different.

Although Figure 16 A illustrates that bias magnet 1600 has comprise multilayer laminated 1604 of three layers 1606,1608 and 1610, in other embodiments, multilayer laminated comprise two-layer or more than three layers.Such as, as shown in Figure 17 A, bias magnet 1700 can comprise comprise 5 layers-1706,1708,1710,1712 and 1714 multilayer laminated 1704.Similar with bias magnet 1600, in two kinds of situations before the annealing of bias magnet 1700 and after annealing, the layer of bias magnet 1700 can produce compositional gradient, its can substantially about with inculating crystal layer 1702 and the roughly equidistant and substantially parallel plane 1734 of coating 1716 symmetrical, as seen in this fig. 17b.

As illustrated in figures 17a and 17b, five layers-1706,1708,1710, every one deck of 1712 and 1714 can be roughly identical thickness.Such as, as above with reference to described in figure 16A and 16B, five layers-1706,1708,1710, every one deck of 1712 and 1714 can have thick reaching thickness.In other examples, 5 layers-1706,1708,1710, every one deck of 1712 and 1714 can have about extremely about thickness, or to have about extremely thickness.In certain embodiments, 5 layers-1706,1708,1710, at least one deck of 1712 and 1714 can have the thickness of at least other one decks being different from 5 layers 1706,1708,1710,1712 and 1714.

In embodiment as illustrated in figures 17a and 17b, inculating crystal layer 1702 and coating 1716 comprise the Pt being roughly 100at.%.In other embodiments, at least one deck of inculating crystal layer 1702 and coating 1716 can be formed by other Pt race elements of such as Pd, Ir, Rh or Ru, can be formed by the alloy of two or more Pt races element, or comprise at least one element that is except Pt race element or alternative Pt race element.Such as, at least one deck of inculating crystal layer 1702 and coating 1716 can comprise except Pt race element or at least one of Mn, Co, Ir, Fe etc. of alternative Pt race element.

Ground floor 1706 and layer 5 1714 are shown as and comprise Pt and Fe alloy by Figure 17 B, and more specifically, this Pt and Fe alloy comprises the Pt as principal ingredient, such as, is rich in Pt alloy.In other embodiments, ground floor 1706 and layer 5 1714 one of at least can comprise higher Fe atomic percent or lower Fe atomic percent, one or more additional elements can be comprised, or the alloy of different element can be comprised, such as, the alloy of at least 2 kinds of Pt race element, Fe, Mn, Co, Ir etc.In addition, although ground floor 1706 and layer 5 1714 are shown as by Figure 17 B comprise roughly the same component, in other embodiments, ground floor 1706 and layer 5 1714 can comprise different component.In other embodiments, at least one deck of ground floor 1706 and layer 5 1714 can comprise and comprise the alloy that principal ingredient is Fe, that is, be rich in Fe alloy.

The second layer 1708 and the 4th layer 1712 are also shown as and comprise Pt and Fe alloy by Figure 17 B, and more specifically, the alloy of this Pt and Fe comprises the Fe as principal ingredient, that is, be rich in Fe alloy.Again, in other embodiments, at least one deck of the second layer 1708 and the 4th layer 1712 can comprise larger Fe atomic percent or less Fe atomic percent, can comprise one or more additional elements, or can comprise the alloy of different element.In certain embodiments, at least one deck of the second layer 1708 and the 4th layer 1712 can comprise the alloy not being rich in Fe, such as, comprises the alloy with the Fe being less than about 50at.%.Additionally, although the second layer 1708 and the 4th layer 1712 are shown as by Figure 17 B have roughly the same component, in other embodiments, the second layer 1708 and the 4th layer 1712 can comprise different component.

Third layer 1710 only can comprise Fe substantially, as seen in this fig. 17b.In other embodiments, third layer 1710 can comprise Fe and Pt alloy, can comprise other elements of such as Pt race, Co, Mn, Ir, or can comprise the alloy of at least two kinds of Fe, Co, Mn, Ir and Pt race element.As mentioned above, in certain embodiments, it is desirable that third layer 1710 has most high magnetic moment, and therefore it comprises the highest Fe atomic percent.The Fe atomic percent of third layer can be greater than the Fe atomic percent of ground floor 1706, the second layer 1708, the 4th layer 1712 and layer 5 1714.

Be similar to bias magnet 1600 (Figure 16), the layer of bias magnet 1700 can be formed as each layer be substantially separated.Such as, after formation, inculating crystal layer can comprise the Pt of roughly 100at.%, and as shown in line 1718, ground floor 1706 can comprise the alloy being rich in Pt represented by line 1720, and the second layer 1708 can comprise the alloy being rich in Fe represented by line 1722.As shown in line 1724, third layer 1710 can comprise the Fe of roughly 100at.%.4th layer of 1712 alloy being rich in Fe that can comprise represented by line 1726, layer 5 1714 can comprise the alloy being rich in Pt represented by line 1728, and coating 1716 can comprise the Pt of roughly 100at.%.

After annealing, the component of bias magnet 1700 can represented by line 1732.Particularly, compared with bias magnet 1700 of annealing can cause distributing with the component of bias magnet 1700 before annealing, fuzzy and level and smooth component distributes.As shown in line 1732, the composition of each layer 1702,1706,1708,1710,1712,1714 and 1716 can diffuse to the adjacent layer of bias magnet 1700 at During Annealing.Such as, a part of Fe of ground floor 1706 can diffuse to inculating crystal layer 1702, and the Pt of inculating crystal layer 1702 can diffuse to ground floor 1706.Similar diffusion also can occur between other adjacent layers, such as, between ground floor 1706 and the second layer 1708, between the second layer 1708 and third layer 1710 etc.These diffusions can cause level and smooth or fuzzy compositional gradient, and the atomic order can being convenient to layer becomes ordered crystal structure, such as L1 ₀phase structure.After although Figure 17 B illustrates annealing comprise rounded step and non-fully level and smooth component distribution (line 1732), in other embodiments, its component distribution can be more level and smooth or more unsmooth compared with shown in Figure 17 B.Specific components distribution after annealing can be the function of multiple parameter, and these parameters comprise, such as, annealing time, annealing temperature, the thickness of layer 1702,1706,1708,1710,1712,1714 and 1716, the component etc. of layer 1702,1706,1708,1710,1712,1714 and 1716.The present invention is open it is conceivable that more level and smooth and more rough other components distribution in any case.

Figure 18 A-18C illustrates the example of bias magnet 1800, and it comprises multilayer laminated 1804 between inculating crystal layer 1802 and coating 1816.Contrary with Figure 16 A, 16B, 17A and 17C example shown, bias magnet 1800 comprises about the asymmetric compositional gradient of plane 1834, this plane and inculating crystal layer 1802 and coating 1816 roughly equidistant and substantially parallel.The part of the generation maximum magnetic field strength controlling bias magnet 1800 can be convenient to about the asymmetric compositional gradient of plane 1834.Figure 18 B and 18C illustrates the example alignment of bias magnet 1800 (Figure 18 B) and read sensor 1828 (Figure 18 C).

As shown in figures 18a and 18b, bias magnet 1800 can comprise four layers under plane 1834: inculating crystal layer 1802, ground floor 1806, the second layer 1808 and third layer 1810.Bias magnet 1800 also can comprise three layers in plane 1834, the 4th layer 1812, layer 5 1814 and coating 1816.In certain embodiments, inculating crystal layer 1802 and coating 1816 can comprise the Pt of roughly 100at.%, as shown by line 1818 and 1830 respectively in Figure 18 A.In other embodiments, as mentioned above, inculating crystal layer 1802 and coating 1816 one of at least can comprise other elements, such as other Pt race elements, Fe, Co, Mn, Ir etc., or comprise the alloy of at least two kinds of these elements.

As shown in Figure 18 A, five layers-1806,1808,1810, every one deck of 1812 and 1814 can comprise different component.In certain embodiments, ground floor 1806 can comprise the alloy of Pt and Fe, more specifically, comprises the alloy that principal ingredient is Pt and Fe of Pt, such as, the alloy being rich in Pt represented by line 1820.In other embodiments, ground floor 1806 can comprise compared to Fe atomic percent more or less shown in Figure 18 A, can comprise one or more additional elements, can comprise the alloy of different element, such as, the alloy of at least two kinds of Pt race element, Fe, Mn, Co, Ir etc.In certain embodiments, ground floor 1806 can comprise the alloy being rich in Fe, that is, comprise the alloy of the Fe being greater than about 50at.%.

The line 1822 of Figure 18 A illustrates the second layer 1808 comprising Pt and Fe alloy, more specifically has the alloy of Pt and Fe of more Fe atomic percents compared to ground floor 1806.Again, in other embodiments, the second layer 1808 can comprise Fe atomic percent more or less compared with shown in Figure 18 A, can comprise one or more additional elements, or can comprise the alloy of different element.In certain embodiments, it is the Pt race element of Fe and the alloy of Fe that the second layer 1808 can comprise principal ingredient, such as, is rich in Fe alloy.

The third layer 1810 represented by line 1824 of Figure 18 A can comprise the alloy that principal ingredient is Pt and Fe of Fe, as shown in Figure 18 A.In other embodiments, third layer 1810 can comprise the alloy of Fe and Pt, this alloy comprises the Fe (comprise and be rich in Pt alloy) of larger number percent or less number percent, another element, such as another Pt race element, Co, Mn, Ir, or the alloy of at least two kinds of Fe, Co, Mn, Ir and Pt race element.As shown in Figure 18 A, every one deck of ground floor 1806, the second layer 1808 and third layer 1810 separately comparable coating 1816 closer to inculating crystal layer 1802.That is, ground floor 1806, the second layer 1808 and third layer 1810 can partially or even wholly be positioned under plane 1834, and plane 1834 is roughly equidistant and parallel with coating 1816 with inculating crystal layer 1802.

As shown in the line 1828 of Figure 18 A, the 4th layer 1812 only can comprise Fe substantially, or substantially can only comprise another element, such as Pt race metal, Co, Ir, Mn etc.In other embodiments, the 4th layer 1812 can comprise the alloy of at least two kinds of Fe, Co, Ir, Mn and Pt race metal.In certain embodiments, the 4th layer 1812 has maximum magnetic moment in ground floor 1806, the second layer 1808, third layer 1810, the 4th layer 1812 and layer 5 1814 is desired.Correspondingly, the 4th layer 1812 can comprise the highest Fe atomic percent, or comprise the highest number percent of another element providing high magnetic moment.

Layer 5 1814, compared with the 4th layer 1812, comprises lower Fe number percent.Such as, as shown in the line 1828 of Figure 18 A, layer 5 1814 can comprise the alloy of Pt and Fe, and this alloy comprises the Pt of Fe and 50at.% of roughly 50at.%.In other embodiments, layer 5 1814 can comprise more Fe atomic percent or less Fe atomic percent.Such as, layer 5 1814 can comprise principal ingredient Fe, such as, be rich in Fe alloy, or comprise principal ingredient Pt, such as, be rich in Pt alloy.In other embodiments, layer 5 1814 can comprise at least one other element, such as example, and another Pt race element, Co, Ir, Mn etc., or comprise the alloy of at least two kinds of Fe, Co, Ir, Mn, Fe, Pt race element etc.

Five layers-1806,1808,1810, at least one deck of 1812 and 1814 can be from five layers-1806,1808,1810, the thickness that at least other one decks are different of 1812 and 1814.Such as, as shown in figures 18a and 18b, ground floor 1806, the second layer 1808 and third layer 1810 can be roughly same thickness.4th layer 1812 and layer 5 1814 also show for having comparable thickness by Figure 18 A and Figure 18 B.In other examples, each layer can be different-thickness, or each layer can be roughly the same thickness.As above with reference in any situation described in figure 16A and 16B, five layers-1706,1708,1710, every one deck of 1712 and 1714 can have thick reaching about thickness.In other embodiments, five layers-1706,1708,1710, every one deck of 1712 and 1714 can have about extremely about thickness, or to have about extremely between thickness.

With bias magnet 1600 (Figure 16 A and 16B) and bias magnet 1700 (Figure 17 A and 17B) similarly, the layer of bias magnet 1800 can be formed as each layer be substantially separated.Such as, after formation, inculating crystal layer 1802 can comprise the Pt of about 100at.%, and as shown in line 1818, ground floor 1806 can comprise the Fe-Pt alloy compositions represented by line 1820, and the second layer 1808 can comprise the Fe-Pt alloy compositions represented by line 1822.Third layer 1810 can comprise the Fe-Pt alloy compositions represented by line 1824, and the 4th layer of 1812 Fe that can comprise the about 100at.% as shown in line 1826.Layer 5 1814 can comprise the Fe-Pt alloy compositions represented by line 1828, and coating 1816 can comprise the Pt of about 100at.%.After annealing, the component of bias magnet 1800 can represented by line 1832.Particularly, compared with magnetic bias 1800 of annealing can cause distributing with the component of magnetic bias 1800 before annealing, fuzzy and level and smooth component distributes.As shown in line 1832, the composition of each layer 1802,1806,1808,1810,1812,1814 and 1816 can diffuse to the adjacent layer of bias magnet 1800 at During Annealing.Such as, a part of Fe of ground floor 1806 can diffuse to inculating crystal layer 1802, and the Pt of inculating crystal layer 1802 can diffuse to ground floor 1806.Similar diffusion also can occur between other adjacent layers, such as, between ground floor 1806 and the second layer 1808, between the second layer 1808 and third layer 1810 etc.These diffusions can cause level and smooth or fuzzy compositional gradient, and the atomic order can being convenient to layer becomes ordered crystal structure, such as L1 ₀phase structure.Although Figure 18 A illustrate annealing after (line 1832) comprise rounded step and non-fully level and smooth component distribution, in other embodiments its component distribution can be more level and smooth or more unsmooth compared with shown in Figure 18 A.Specific components distribution after annealing can be the function of multiple parameter, and these parameters comprise, such as, annealing time, annealing temperature, the thickness of layer 1802,1806,1808,1810,1812,1814 and 1816, the component etc. of layer 1802,1806,1808,1810,1812,1814 and 1816.The present invention is open it is conceivable that other more level and smooth and more rough in any case components distribution.

Figure 18 B and Figure 18 C illustrates the alignment of bias magnet 1800 and example read sensor 1838.Read sensor 1838 can be similar to the tunnel magneto sensor 218 shown in Fig. 2.Particularly, sensor 1838 can comprise antiferromagnetic inculating crystal layer 1850, pinning layer 1848, key horizon 1846, tunnel barriers 1844, free layer 1842 and coating 1840.As shown in Figure 18 B and 18C, the 4th layer 1812 of bias magnet 1800 can align with the free layer 1842 of read sensor 1838 substantially.As mentioned above, the 4th layer 1812 can comprise the highest Fe atomic percent, and therefore can have the highest magnetic moment.Ground floor 1806, the second layer 1808, third layer 1810 and layer 5 1814 can comprise lower Fe atomic percent compared with the 4th layer 1812, and therefore have lower magnetic moment.The magnetic moment of free layer 1842 can be biased by the magnetic moment of substantial alignment the 4th layer 1812 and free layer the 1842, four layer 1812, and the remainder layer of read sensor 1838 can not be affected largely.In addition, the magnetic moment of inculating crystal layer 1802, ground floor 1806, the second layer 1808, third layer 1810, layer 5 1814 and coating 1816 can be less than the magnetic moment of the 4th layer 1812, if and adjacent to read sensor 1838 remainder layer place time, compared with the layer had similar in appearance to the magnetic moment of the 4th layer 1812, the remainder layer of read sensor 1838 can be affected to lesser extent.Like this, the structure of bias magnet 1800 can reduce bias magnet 1800 magnetic moment on the layer of read sensor 1838 but not undesirable impact of free layer 1842.

As shown in Figure 18 B and 18C, the 4th layer 1812 and free layer 1842 accurately do not align.Such as, the 4th layer 1812 thicker than free layer 1842.In other embodiments, the 4th layer 1812 and free layer 1842 can align more completely.Such as, the 4th layer 1812 and free layer 1842 can have roughly the same thickness.In other embodiments, the 4th layer 1812 and free layer 1842 can more inaccurately align.Such as, the border of the 4th layer 1812 and free layer 1842 all can not line up, and the 4th layer 1812 and free layer 1842 can have different-thickness.

Although Figure 18 A and 18B illustrate comprise have five layers-1806,1808,1810,1812 and 1814 multilayer laminated 1804, and comprise the bias magnet 1800 of asymmetric component distribution, but in other embodiments, bias magnet can comprise and be less than five or layer more than five, and has the distribution of asymmetric component.Such as, bias magnet can comprise four layers or six layers, and can have the distribution of asymmetric component.In addition, the alignment of bias magnet 1800 and read sensor 1838 can be different from shown in Figure 18 B and 18C.Such as, third layer 1810 and free layer 1842 can roughly align, or layer 5 1814 and free layer 1842 can roughly align.Other alignment of bias magnet 1800 and read sensor 1838 are apparent, and the present invention open it is conceivable that.

In certain embodiments, comprise multilayer laminated bias magnet and can not comprise compositional gradient, but alternatively can be included in whole multilayer laminated in roughly uniform component distribution.As illustrated in fig. 19 a and fig. 19b, such as, bias magnet 1900 can comprise inculating crystal layer 1902, coating 1916, and comprise five layers-1906,1908,1910,1912 and 1914 multilayer laminated 1904.Bias magnet 1900 is shown for comprising Pt and Fe by Figure 19 A and 19B.In other embodiments, bias magnet 1900 can comprise Fe and another Pt race element, such as Pd, Ir, Rh or Ru etc., or comprises at least two kinds of Co, Ir, Mn, Fe and Pt race element.

In the embodiment shown, inculating crystal layer 1902 and coating 1916 comprise the Pt of about 100at.% separately.In other embodiments, one of at least can being formed by another Pt race element of inculating crystal layer 1902 and coating 1916, such as, Pd, Ir, Rh or Ru etc., can be formed by two or more elements of Pt race element, or can comprise except Pt race element or at least one element of alternative Pt race element.Such as, inculating crystal layer 1902 and coating 1916 one of at least can comprise except Pt race element or at least one of Mn, Co, Ir, Fe etc. of alternative Pt race element.

Ground floor 1906, third layer 1910 and layer 5 1914 are shown to be the alloy comprising Pt and Fe by Figure 19 B, and more specifically, the alloy of Pt and Fe comprises the Fe as principal ingredient, such as, is rich in Fe alloy.In other embodiments, ground floor 1906, third layer 1910 and layer 5 1914 one of at least can comprise more or less Fe atomic percent, one or more additional elements can be comprised, or the alloy of different element can be comprised, such as, the alloy of at least two kinds of Pt race element, Fe, Mn, Co, Ir etc.In addition, although ground floor 1906, third layer 1910 and layer 5 1914 are shown as by Figure 19 B have roughly the same component, in other embodiments, ground floor 1906, third layer 1910 and layer 5 1914 one of at least can comprise different component.In other embodiments, one of at least can comprising of ground floor 1906, third layer 1910 and layer 5 1914 comprises the alloy that principal ingredient is Pt, that is, be rich in Pt alloy.

The second layer 1908 and the 4th layer 1912 are also shown to be the alloy comprising Pt and Fe by Figure 19 B, and more specifically, the alloy of Pt and Fe comprises principal ingredient Pt, that is, be rich in Pt alloy.Again, in other embodiments, the second layer 1908 and the 4th layer 1912 one of at least can comprise larger or less Fe atomic percent, one or more additional elements can be comprised, or the alloy of different element can be comprised.In certain embodiments, the second layer 1908 and the 4th layer 1912 one of at least can comprise the alloy not being rich in Fe, such as, comprise the alloy of the Fe being less than 50at.%.In addition, although Figure 19 B is shown as the second layer 1908 and the 4th layer 1912 there is roughly the same component, in other embodiments, the second layer 1908 and the 4th layer 1912 can comprise different component.

Inculating crystal layer 1902, ground floor 1906, the second layer 1908, third layer 1910, the 4th layer 1912, every one deck of layer 5 1914 and coating 1916 can comprise the component being different from component shown in Figure 19 B.Such as, inculating crystal layer 1902, ground floor 1906, the second layer 1908, third layer 1910, the 4th layer 1912, layer 5 1914 and coating 1916 one of at least can comprise more Fe atomic percent or less Fe atomic percent.Inculating crystal layer 1902, ground floor 1906, the second layer 1908, third layer 1910, the 4th layer 1912, the different component one of at least of layer 5 1914 and coating 1916 can cause bias magnet to have different component distribution after bias magnet 1900 anneals front and/or annealing.

With bias magnet 1600 (Figure 16 A) similarly, the layer of bias magnet 1900 can be formed as each layer be substantially separated.Such as, after formation, inculating crystal layer 1902 can comprise the Pt of about 100at.%, and as shown in line 1912, ground floor 1906 can comprise the alloy compositions being rich in Fe represented by line 1920, and the second layer 1908 can comprise the alloy compositions being rich in Pt represented by line 1922.Third layer 1910 can comprise the alloy being rich in Fe, as shown in line 1924, can comprise the alloy compositions being rich in Pt represented by line 1926 for 4th layer 1912, layer 5 1914 can comprise the alloy compositions being rich in Fe represented by line 1928, and coating 1916 can comprise the Pt of about 100at.%.

After annealing, the component of bias magnet 1900 can be represented by line 1932.Particularly, compared with bias magnet 1900 of annealing can cause distributing with the component of bias magnet 1900 before annealing, fuzzy and level and smooth component distributes.As shown in line 1932, the composition of each layer 1902,1906,1908,1910,1912,1914 and 1916 can diffuse to the adjacent layer of bias magnet 1900 at During Annealing.Such as, the part Fe of ground floor 1906 can diffuse to inculating crystal layer 1902, and the Pt of inculating crystal layer 1902 can diffuse to ground floor 1906.Similar diffusion also can occur between other layers, such as, between ground floor 1906 and the second layer 1908, between the second layer 1908 and third layer 1910 etc.These diffusions can cause level and smooth or fuzzy component distribution, and the atomic order can being convenient to layer becomes ordered crystal structure, such as L1 ₀phase structure.After although Figure 19 B illustrates annealing comprise rounded step and non-fully level and smooth component distribution (line 1932), in other embodiments, its component distribution can be more level and smooth or more unsmooth compared with shown in Figure 19 B.Specific components distribution after annealing can be the function of multiple parameter, and these parameters comprise, such as, annealing time, annealing temperature, the thickness of layer 1902,1906,1908,1910,1912,1914 and 1916, the component etc. of layer 1902,1906,1908,1910,1912,1914 and 1916.The present invention is open it is conceivable that more level and smooth and more rough other components distribution in any case.

In certain embodiments, bias magnet can comprise multilayer laminated, this multilayer laminated layer comprised greater or less than five layers.In certain embodiments, with have fewer layers multilayer laminated compared with, comprise and more multi-layered multilayer laminatedly reduce the annealing temperature formed needed for orderly phase structure.

Figure 20 is the process flow diagram of example technique, can form the bias magnet of such as bias magnet 1600 (Figure 16 A) according to this technology.First, inculating crystal layer 1602 (2002) can be formed.Inculating crystal layer 1602 can be formed by any technology in various technology, such as, and sputtering, ion beam depositing, chemical vapor deposition, physical vapour deposition (PVD), molecular beam epitaxy, laser ablation etc.Inculating crystal layer 1602 can be formed on various substrate, such as example insulating material 222 or 223 etc. (Fig. 2).As mentioned above, inculating crystal layer 1602 can have thick reaching about thickness, in certain embodiments, can have about peace treaty between thickness.

Multilayer laminated 1604 are formed at (2004) on inculating crystal layer 1602.As described in reference to figure 16A and 16B, multilayer laminated 1604 can comprise two-layer, three layers or more than three layers.Layer in multilayer laminated 1604 can comprise similar or different components.Every one deck of ground floor 1606 in multilayer laminated 1604, the second layer 1608 and third layer 1610 can be formed respectively, every one deck of ground floor 1606, the second layer 1608 and third layer 1610 by such as ion beam depositing, the formation such as chemical vapor deposition, physical vapour deposition (PVD), molecular beam epitaxy, laser ablation.Ground floor 1606, the second layer 1608 and third layer 1610 can have thick reaching about separately thickness.In certain embodiments, ground floor 1606, the second layer 1608 and third layer 1610 one of at least can have about peace treaty between thickness, in other embodiments, one of at least can having about of ground floor 1606, the second layer 1608 and third layer 1610 peace treaty between thickness.

Once define the layer of multilayer laminated 1604, coating 1612 just can be formed at (2006) on multilayer laminated 1604.Coating 1612 by, such as, the formation such as sputtering, ion beam depositing, chemical vapor deposition, physical vapour deposition (PVD), molecular beam epitaxy, laser ablation.As mentioned above, coating 1612 can have thick reaching about thickness, in certain embodiments, can have about peace treaty between thickness.

Finally, (2008) can be annealed to bias magnet 1600.Such as, bias magnet 1600 can be annealed about 6 hours under about 200 DEG C to the temperature in the scope of 500 DEG C.In certain embodiments, bias magnet 1600 can be annealed to the temperature in the scope of 300 DEG C at about 200 DEG C, or anneals at about 280 DEG C.In certain embodiments, the annealing of 4 hours is approximately carried out.The diffusion of at least one composition between the adjacent layer that the annealing of bias magnet 1600 can be convenient to magnetic bias 1600.These diffusions can be convenient to form ordered phase, such as L1 ₀ordered phase.This diffusion also can cause evenly component, such as Figure 19 A and 19B, or more level and smooth compositional gradient can be caused, such as Figure 16 A, 16B, 17A, 17B, 18A and 18B.

example

Figure 21 is four kinds of different iron-magnetic moments of platinum hard magnetic body and the graph of relation in magnetic field.Curve 2102 expression comprises Pt inculating crystal layer, is rich in the remanent magnetism coercive force of the hard magnetic body of the FePt alloy interlayer of Fe and Pt coating, and this hard magnetic body is annealed at about 280 DEG C.Curve 2104 represents and comprises pt inculating crystal layer, comprise the Pt of Fe and 60at.% of 40at.% layer, comprise the Pt of Fe and 35at.% of 65at.% layer, comprise the Pt of Fe and 60at.% of 40at.% layer and the remanent magnetism coercive force of hard magnetic body of Pt coating, this hard magnetic body is annealed at about 280 DEG C.Curve 2106 expression comprises Pt inculating crystal layer, is rich in the remanent magnetism coercive force of the hard magnetic body of the FePt alloy interlayer of Fe and Pt coating, and this hard magnetic body is annealed at about 300 DEG C.Curve 2108 represents and comprises pt inculating crystal layer, comprise the Pt of Fe and 60at.% of 40at.% layer, comprise the Pt of Fe and 35at.% of 65at.% layer, comprise the Pt of Fe and 60at.% of 40at.% layer and the remanent magnetism coercive force of hard magnetic body of Pt coating, this hard magnetic body is annealed at about 300 DEG C.

As shown in figure 21, the remanent magnetism coercive force 1400Oe more about than the remanent magnetism coercive force of the hard magnetic body represented by curve 2106 that the hard magnetic body represented by curve 2108 has.This proves, when annealing at roughly the same temperature, multilayer laminatedly causing hard magnetic body than the hard magnetic body comprising single middle layer and has larger remanent magnetism coercive force.

Curve 2104 and 2106 illustrate comprise multilayer laminated hard magnetic body be about anneal at the temperature of 280 DEG C time, the remanent magnetism coercive force suitable with the remanent magnetism coercive force of the hard magnetic body of annealing at about 300 DEG C with single middle layer can be had.Correspondingly, the comparison of curve 2104 and 2106 proves that chemically ordered temperature can reduce due to the multilayer laminated use between inculating crystal layer and coating.

Describe various embodiment of the present invention.Above-mentioned realization and other realizations fall in the scope of following claim.

Claims

1. a hard magnetic body, comprising:

Inculating crystal layer, it comprises the first composition, and described first composition comprises at least one of Pt race metal;

Coating, it comprises described first composition; And

Multilayer laminated, it is between described inculating crystal layer and described coating, wherein saidly multilayer laminatedly to comprise:

Ground floor, it comprises first alloy of described first composition and Fe;

The second layer, it to be formed on described ground floor and to comprise Fe; And

Third layer, it to be formed on the described second layer and to comprise the 3rd alloy of described first composition and Fe, and wherein said first alloy and described 3rd alloy all comprise the Fe atomic percent fewer than the described second layer,

Wherein said hard magnetic body comprises the magnetocrystalline grain with magnetic aligning in face.

2. hard magnetic body as claimed in claim 1, it is characterized in that, described Pt race metal comprises Pt.

3. hard magnetic body as claimed in claim 1, it is characterized in that, describedly multilayer laminatedly also comprise the layer 5 being formed on described ground floor the 4th layer and being formed on described 4th layer, wherein said 4th layer of the 4th alloy comprising Fe and Pt race metal, it comprises more than described first alloy but fewer than described second layer Fe atomic percent, and wherein said layer 5 comprises the pentahapto gold of Fe and Pt race metal, it comprises the Fe atomic percent more than described 4th alloy.

4. hard magnetic body as claimed in claim 1, is characterized in that, the component distribution of described hard magnetic body substantially about with described inculating crystal layer and the roughly equidistant and substantially parallel plane symmetry of described coating.

5. hard magnetic body as claimed in claim 1, is characterized in that, the component distribution of described hard magnetic body about with described inculating crystal layer and the roughly equidistant and substantially parallel plane of described coating asymmetric.

6. hard magnetic body as claimed in claim 1, is characterized in that, one of at least comprising about of described ground floor, the described second layer and described third layer peace treaty between thickness.

7., for a read-write head for data storage device, described read-write head comprises:

Hard magnetic body, it comprise comprise Pt race metal inculating crystal layer, comprise the coating of Pt race metal and multilayer laminated between described inculating crystal layer and described coating, wherein saidly multilayer laminatedly to comprise:

Ground floor, it comprises first alloy of described Pt race metal and Fe;

Third layer, it to be formed on the described second layer and to comprise the 3rd alloy of described Pt race metal and Fe, and wherein said first alloy and described 3rd alloy all comprise the Fe atomic percent fewer than the described second layer,

8. read-write head as claimed in claim 7, is characterized in that, described ground floor, the described second layer and described third layer one of at least comprise thick reaching about thickness.

9. read-write head as claimed in claim 7, is characterized in that, one of at least comprising about of described ground floor, the described second layer and described third layer peace treaty between thickness.

10. read-write head as claimed in claim 7, also comprise the read sensor comprising free layer, the wherein said second layer roughly aligns with described free layer.

11. read-write heads according to claim 7, it is characterized in that, describedly multilayer laminatedly also comprise the 4th layer that is formed on described ground floor, and the layer 5 be formed on described 4th layer, wherein said 4th layer of the 4th alloy comprising Fe and Pt race metal, it comprises higher than described first alloy but lower than described second layer Fe atomic percent, and wherein said layer 5 comprises the pentahapto gold of Fe and Pt race metal, and it comprises the Fe atomic percent higher than described 4th alloy.

12. read-write heads according to claim 11, also comprise the read sensor comprising free layer, and the wherein said second layer roughly aligns with described free layer.

13. read-write heads according to claim 7, is characterized in that, the distribution of the component of described hard magnetic body substantially about with described inculating crystal layer and the roughly equidistant and substantially parallel plane symmetry of described coating.

14. read-write heads according to claim 7, is characterized in that, the distribution of the component of described hard magnetic body substantially about with described inculating crystal layer and the roughly equidistant and substantially parallel plane of described coating asymmetric.

15. 1 kinds of methods forming hard magnetic body, comprising:

Form the inculating crystal layer comprising the first composition, described first composition comprises at least one of Pt race metal;

Formed multilayer laminated on described inculating crystal layer, wherein saidly multilayer laminatedly to comprise: the ground floor comprising first alloy of described first composition and Fe; To be formed on described ground floor and to comprise the second layer of Fe; And to be formed on the described second layer and to comprise the third layer of the 3rd alloy of described first composition and Fe, wherein said first alloy and described 3rd alloy all comprise the Fe atomic percent fewer than the described second layer; And

Described multilayer laminated on form coating, wherein said coating comprises described first composition; And

Described inculating crystal layer, described multilayer laminated and described coating are heated to annealing temperature, to cause phase counterdiffusion between the adjacent layer of described inculating crystal layer, described multilayer laminated and described coating,

16. methods as claimed in claim 15, is characterized in that, described multi-layer laminate structure are heated to annealing temperature and comprise and being heated between about 250 DEG C and about 300 DEG C by described multi-layer laminate structure.