US20080197021A1

US20080197021A1 - Method to make superior soft (low Hk), high moment magnetic film and its application in writer heads

Info

Publication number: US20080197021A1
Application number: US11/707,826
Authority: US
Inventors: Xiaomin Liu; Cherng-Chyi Han; Feiyue Li
Original assignee: Headway Technologies Inc
Current assignee: Headway Technologies Inc
Priority date: 2007-02-16
Filing date: 2007-02-16
Publication date: 2008-08-21
Also published as: JP2008205472A

Abstract

A process sequence for forming a soft magnetic layer having Hce and Hch of ≦2 Oe, Hk≦5 Oe, and Bs of ≧24 kG is disclosed. A CoFe or CoFe alloy is electroplated in a 10^OC to 25^OC. bath (pH 2 to 3) containing Co⁺²and Fe⁺²ions in addition to boric acid and one or more aryl sulfinate salts to promote magnetic softness in the deposited layer. Peak current density is 30 to 60 mA/cm². A two step magnetic anneal process is performed to further improve softness. An easy axis anneal is followed by a hard axis anneal or vice versa. In an embodiment where the magnetic layer is a pole layer in a write head, the temperature is maintained in a 180^OC to 250^OC range and the applied magnetic field is kept a 300 Oe or below to prevent degradation of an adjacent read head.

Description

FIELD OF THE INVENTION

The invention relates to an electroplating method for CoFe based alloys that have low coercivity and low Hk but with high magnetic moment required for high density magnetic recording.

BACKGROUND OF THE INVENTION

Electroplating methods are commonly used in numerous applications such as depositing metal films including copper interconnects in semiconductor devices and forming magnetic layers in magnetic recording devices. Although magnetic layers in read and write heads may be deposited by a sputtering method, an electroplating process is usually preferred because the sputtering process produces a magnetic layer with a large magnetocrystalline anisotropy and higher internal stress. Electroplating is capable of generating a magnetic layer with a smaller crystal grain size and a smoother surface that leads to a high magnetic flux density (Bs) value and low coercive force (Hc).
In an electroplating process, an electric current is passed through an electroplating cell comprised of a working electrode (cathode), counter electrode (anode), and an aqueous electrolyte solution of positive ions of the metals to be plated on a substrate in physical contact with the cathode. By applying a potential to the electrodes, an electrochemical process is initiated wherein cations migrate to the cathode and anions migrate to the anode. Metallic ions such as Fe⁺², Co⁺², and Ni⁺²deposit on a substrate (cathode) to form an alloy that may be NiFe, CoFe, or CoNiFe, for example. The substrate typically has an uppermost seed layer on which a photoresist layer is patterned to provide openings over the seed layer that define the shape of the metal layer to be plated. Once the metal layer is deposited, the photoresist layer is removed. The magnetic layers which become a bottom pole layer and top pole layer in a write head can be formed in this manner.
For high density magnetic recording, writer materials require high saturation magnetization to write on high coercivity media. Almost all of the materials with high saturation magnetization (higher than 23 kG) are CoFe based alloys which usually have a relatively large anisotropy field (Hk) of about 15 Oe or higher. Unfortunately, a high anisotropy field will decrease the permeability of the writer and thereby decrease its effectiveness in high density and high frequency recording applications. Thus, an improved electroplating method is needed that can deposit a CoFe based alloy having a low coercivity (Hc) and low Hk but with a high saturation magnetization (Bs).
During a routine search of the prior art, the following references relating to electroplating methods were found. U.S. Pat. No. 4,756,816 discloses a plating bath for a CoFe layer.
In related U.S. Pat. Nos. 4,014,759 and 4,053,373, α-hydroxy sulfones made from an aromatic sulfinate and an aldehyde are used in a plating bath to correct deficiencies such as loss of leveling, brightness and covering power in CoFe deposited layers.
A method for depositing a soft CoFe alloy film having a high saturation magnetization is described in U.S. Pat. No. 6,855,240 and includes the use of an aromatic sulfinic acid or salt thereof.
In U.S. Patent Publication 2005/0252576, a two step anneal method is described in which a spin valve structure is annealed at about 250^OC with a 10000 Oe applied field and then reducing the field to about 500 Oe before cooling to set the magnetization direction of the AP1 and AP2 layers in the pinned ferromagnetic layer. The process is repeated after the hard bias layers and electrical leads are formed. In both cases, the magnetic moments are set along the easy axis.

SUMMARY OF THE INVENTION

One objective of the present invention is to provide an electrodeposition method and magnetic annealing process for forming a soft magnetic film with a high saturation moment of at least 24 kG.
A further objective of the present invention is to provide a process according to the first objective that yields a magnetic layer having an Hce (easy axis coercivity) and Hch (hard axis coercivity) of less than 2 Oe with an Hk of less than 5 Oe.
According to one embodiment of the present invention, an electroplating process followed by a two step anneal yields a soft magnetic layer that is especially suitable for high density and high frequency magnetic recording as in thin film magnetic heads. High density is defined as >150 Gb/in²and high frequency is considered to be >1 GHz. In one embodiment, a substrate is provided upon which a seed layer has been formed. Above the seed layer is a patterned photoresist layer with openings that correspond to the shape of the desired magnetic layer to be deposited in a subsequent step. A CoFe or CoFe alloy such as CoFeNi is then electroplated on the substrate in an electroplating cell comprised of an anode and a cathode (working electrode) which are immersed in an electrolyte solution. A reference electrode with a stable, fixed voltage may be employed. Furthermore, there is a power source (potentiostat) with leads affixed thereto wherein one lead connects to the anode and supplies a positive voltage and a second lead connects to the cathode to provide a negative voltage when the cell is operating. A third lead connects to the reference electrode. In the exemplary embodiment, the aqueous based electrolyte solution is comprised of ferrous sulfate, cobalt sulfate, boric acid as a buffer agent, an electric supporting agent, and aryl sulfinates and is maintained at a pH between 2 and 3. A stress reducer, surfactant, and an additional metal sulfate such as nickel sulfate may be added to modify certain properties in the plated layer. A soft magnetic layer is deposited that may be up to 2.5 microns in thickness.
A key feature of the present invention is that a two step magnetic anneal process is used to further improve magnetic softness. In one embodiment, the electroplated film on the substrate is first subjected to an easy axis anneal and subsequently to a hard axis anneal in a second step. In an alternative embodiment, the electroplated film is first subjected to a hard axis anneal and subsequently to an easy axis anneal. The temperature during the annealing steps is maintained in the 180^OC to 250^OC range to avoid damage to the MTJ element in an adjacent read head which is typically formed prior to fabricating the write head and annealing the soft, high moment magnetic layer. Furthermore, the applied magnetic field during the annealing steps is preferably less than 300 Oe so as not to change the preferred direction of magnetic moment in the pinned layer in the MTJ element and thereby maintain read head performance. The resulting soft magnetic layer has an Hce and Hch of less than about 2 Oe and Hk is reduced to less than 5 Oe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating an example of an electroplating system that could be used in the process of the present invention.

FIG. 2 a is a B—H loops plot of an as-plated CoFe based film and FIG. 2 b is a similar plot following easy axis anneal of the film.

FIG. 3 a is a B—H loops plot of an as-plated CoFe based film and FIG. 3 b is a similar plot following hard axis anneal of the film.

FIG. 4 is a B—H loops plot of an electroplated CoFe based film after a two step magnetic anneal in which an easy axis anneal step is followed by a hard axis anneal step according to a first embodiment of the present invention.

FIG. 5 is a B—H loops plot of an electroplated CoFe based film after a two step magnetic anneal in which a hard axis anneal step is followed by an easy axis anneal step according to a second embodiment of the present invention.

FIG. 6 a is a B—H loops plot of a sputter deposited Co₃₀Fe₇₀film before anneal and

FIG. 6 b is a similar plot following a two step magnetic anneal according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a method of forming a soft magnetic layer with high saturation magnetization in addition to low Hc and Hk values that is useful for high density and high frequency recording applications. The method disclosed herein comprises an electroplating process followed by a two step anneal process to form magnetic layers such as bottom and top pole layers in magnetic recording devices or cladding layers on conductive lines in MRAM devices as appreciated by those skilled in the art. The drawings are provided by way of example and are not intended to limit the scope of the invention. The terms electroplating and electrodeposition may be used interchangeably.
Referring to FIG. 1, one example of an electroplating cell configuration that may be employed to carry out the process of the present invention is shown. However, other conventional electroplating cells such as commercially available electroplating systems are also acceptable. It should be understood that the magnetic layer deposited according to the present invention is preferably formed on a seed layer (not shown) disposed on a substrate. For example, the substrate may be a write gap layer in a partially formed write head. Furthermore, the partially completed write head may be formed on a read head structure in a combined read/write head configuration. The seed layer may be deposited by a sputtering process and preferably has the same composition as intended for the subsequently formed magnetic layer. Typically, the fabrication process involves forming a seed layer on a substrate and then patterning a photoresist layer on the seed layer to define openings that dictate the shape of the magnetic layer. The seed layer promotes the deposition of the magnetic layer during the electroplating process. Once the magnetic layer is electroplated, the photoresist layer and underlying portions of the seed layer are removed.
In one aspect, the electroplated magnetic layer is comprised of a soft magnetic material having a certain thickness and is CoFe or an alloy thereof such as CoFeNi or the like. In another embodiment, the electroplated magnetic layer may be comprised of another soft magnetic material that may be NiFe or a NiFe alloy, for example. When the soft magnetic layer is a pole layer in a write head, the certain thickness is about 2 to 3 microns. However, the thickness of an electroplated magnetic layer according to the present invention may be less than 2 microns as appreciated by those skilled in the art.
Returning to FIG. 1, the electroplating system 1 used to deposit a soft magnetic layer according to the present invention may be comprised of a container 2 such as a tank and an electrolyte solution 3 having a top surface 3 a contained therein. There is a means such as a pump and paddle for circulating the electrolyte solution 3 and a reservoir to replenish the solution that are not shown. In the exemplary embodiment, the electrolyte solution 3 is aqueous based and is comprised of Fe⁺²and Co⁺²salts and optionally with one or more other metal cations such as Ni⁺²that are added as chloride and/or sulfate salts. Boric acid (H₃BO₃) is preferably added to buffer the electrolyte solution 3 and thereby maintain a pH in the range of 2.0 to 3.0. The electrolyte solution 3 also contains one or more aryl sulfinate salts such as sodium benzenesulfinate to reduce the amount of brighteners and leveling agents necessary for optimum properties in the electroplated magnetic layer and also to improve magnetic softness in the electroplated film. Other additives may be employed to optimize the performance of the electrolyte solution. For example, saccharin may be used as a stress reducing agent and sodium lauryl sulfate may serve as a surfactant. In one embodiment, the electrolyte solution 3 is maintained at a temperature between 10^OC and 25^OC and is mechanically agitated by a rotating paddle or the like during the electroplating process. Furthermore, either a direct current (DC) or pulsed DC mode may be used with a duty ratio of about 15% to 40% and a cycle time of about 30 to 150 ms to supply a peak current density of 30 to 60 mA/cm²that powers the electroplating process.
There is a counter electrode (anode) 4 and a working electrode also known as a cathode 5 immersed or otherwise positioned in the electrolyte solution 3. When a magnetic layer made of CoFe, CoFeNi, or the like is electroplated, the anode 4 is preferably Co (or Ni) and a positive potential is applied thereto. In an embodiment where a CoFe alloy is electroplated, the anode 4 may be comprised of Co. The cathode 5 may be a dimensionally stable electrode such as Pt or gold mesh to which a negative potential is applied. In other words, a potential hereafter referred to as an electroplating potential is established between the anode 4 and cathode 5 whereby an electric current flows from the anode to the cathode to drive the electroplating process. The substrate 9 is preferably in good electrical contact with the cathode 5 and may be affixed thereto by a clamp or other conventional means. Although the anode 4 and cathode 5 (and substrate 9) are shown opposed to each other on opposite walls of the container 2, the anode and cathode may optionally be arranged in other configurations. For instance, the anode and cathode may have their top and bottom surfaces aligned parallel to the top surface 3 a of the electrolyte solution. The substrate 9 and specifically a seed layer thereon that is exposed through openings in a photoresist pattern (not shown) functions as a cathode during the electroplating process.
The anode 4 and cathode 5 are connected to a potentiostat (power source) 7 by electrical leads 8 a and 8 b, respectively. There is also a reference electrode 6 immersed in the electrolyte solution 3 and connected to the potentiostat 7 by a lead 8 c. Preferably, the reference electrode 6 is positioned in the vicinity of the anode 5. The reference electrode 6 may be a standard calomel electrode (SCE) comprised of Hg/HgCl₂in a KCl electrolyte or may be a silver/silver chloride electrode as appreciated by those skilled in the art.
Another feature shown in FIG. 1 is a magnetic field generator 10 that is located adjacent to the container 2 near the cathode 5. The magnetic generator 10 may be used to influence the magnetic orientation of a magnetic layer (not shown) which is deposited on the substrate 9 during the electroplating process. A magnetic field produced by the magnetic generator 10 may be used during plating to form anisotropic magnetic films as depicted in FIGS. 2 a, 3 a.
In one embodiment wherein CoFe or CoNiFe is electroplated on a substrate, the electrolyte solution 3 is an aqueous solution having a pH between 2.0 and 3.0 and includes Fe⁺²ions, Co⁺²ions, and optionally, Ni⁺²ions (for CoFeNi deposition) which are provided by adding the following metal salts to deionized water at the indicated concentrations in grams per liter: FeSO₄.7H₂O (50 to 140 g/L); CoSO₄.7H₂O (20 to 70 g/L); and NiSO₄.6H₂O (0 to 70 g/L). Additionally, the electrolyte solution may be comprised of other additives and supporting electrolytes including but not limited to H₃BO₃with a concentration of 20 to 40 g/L, NaCl as an electrolyte supporting agent at a concentration of 0 to 20 g/L, (NH₄)₂SO₄or NH₄Cl as an electrolyte supporting agent at a concentration of 0 to 30 g/L, sodium saccharin as a stress reducing agent at a concentration of 0 to 2.0 g/L, sodium lauryl sulfate as a surfactant at a concentration of 0 to 0.15 g/L, and one or more aryl sulfinate salts including sodium benzene sulfinate at a concentration of 0.05 to 0.3 g/L to improve the magnetic softness of the electroplated magnetic layer. Preferably, the electroplating is performed with an electrolyte solution temperature between 10^OC and 25^OC and with a plating current density of from 30 to 60 mA/cm². The duty ratio during each cycle may vary and is based on an “ON” time of 10 to 50 ms and an “OFF” time of 20 to 200 ms. Using these conditions, a magnetic layer comprised of CoFe or CoNiFe is deposited at the rate of about 500 to 1700 Angstroms per minute. Typically, the electroplating process is terminated after a predetermined length of time that corresponds to a desired thickness.
In an embodiment wherein a CoFe magnetic layer is electodeposited on a substrate, the composition is preferably between 25 and 35 atomic % Co and from 65 to 75 atomic % Fe. When a CoFeNi magnetic layer is electroplated, the preferred composition is between 25 and 35 atomic % Co, from 65 to 75 atomic % Fe, and between 2 and 4 atomic % Ni. The aforementioned electroplating conditions produce a magnetic layer with low coercivity (Hce<8 Oe, Hch<1 Oe), low anisotropy field (Hk<10 Oe), and high saturation magnetization (Bs≧24 kG).
The inventors have previously practiced a magnetic anneal process involving one anneal step to further improve magnetic softness in the electroplated layer. Note that the annealing step is preferably carried out in an oven after the electroplated substrate is removed from the electroplating bath. Magnetic annealing is one of the most common methods used with magnetic layers in write heads in order to improve writer performance. Generally, only a hard-axis anneal or an easy-axis anneal is employed during writer fabrication. Although a one step magnetic anneal can reduce film coercivity, it cannot reduce the anisotropy field of a CoFe based high moment magnetic layer in a write head. For example, FIG. 2 a shows the B—H loops plot of an as-plated CoFe magnetic layer before annealing and FIG. 2 b shows the B—H loops plot for the same film after easy-axis annealing. The results indicate an easy-axis anneal can reduce easy axis coercivity (Hce) from 6.9 to 3.1 Oe and hard axis coercivity (Hch) from 0.8 to 0.3 Oe. However, Hk increased from 9.9 to 13.7 Oe after the easy axis anneal.
In an example where the plated magnetic layer is a write pole layer, the easy axis may be an axis that is parallel to the ABS plane and the hard axis intersects the easy axis and is perpendicular to the ABS plane.
Referring to FIG. 3 a, the B—H loops plot of an as-plated CoFe magnetic layer (Co₃₀Fe₇₀) is depicted before annealing. A similar plot is shown in FIG. 3 b for the film after a single anneal involving a hard-axis anneal step. Following the hard-axis anneal, the induced film easy axis rotated 90 degrees. In this case, Hc along the original easy axis direction is reduced from 6.8 to 0.2 Oe and Hc along the original hard axis direction increased from 0.8 to 3.0 Oe. Thus, hard-axis anneal can only change the direction of the anisotropy field. Hk is still 9.8 Oe after hard-axis anneal which means a one step anneal cannot reduce the amplitude of the anisotropy field (Hk) to less than the desired 5 Oe target value.
A key feature of the present invention is the introduction of a two step anneal process in which the electroplated magnetic layer is subjected to a hard axis anneal and an easy axis anneal. The anneal steps are preferably performed at a temperature between 180^OC and 250^OC so that a read head adjacent to the write head in a combined read/write head structure is not damaged. In addition, the applied magnetic field during the anneal steps is kept at 300 Oe or less to prevent altering the preferred direction of magnetic moment in the pinned layer within the read head. According to one embodiment, the applied magnetic field during the easy axis anneal and hard axis anneal is between about 200 Oe and 300 Oe.
The inventors have surprisingly discovered that by subjecting the electroplated magnetic layer formed according to a method of the present invention to a two step anneal process, the softness (Hce and Hch) of the magnetic layer is further reduced and the anisotropy field is also lowered unlike single anneal examples. In one embodiment, the soft magnetic layer described previously is first treated with an easy axis anneal and then with a hard axis anneal in a second step. The length of each anneal step is between 20 and 300 minutes and is preferably greater than 30 minutes. Preferably, the substrate is cooled to room temperature for a certain length of time between the two anneal steps. In the exemplary embodiment, the magnitude of the applied magnetic field is maintained at the same level for the two annealing steps. However, one skilled in the art will appreciate that the present invention also anticipates an additional embodiment wherein the applied magnetic field during the easy axis anneal is unequal to that during the hard axis anneal step.
Referring to FIG. 4, a B—H loops plot of a CoFe magnetic layer that has been electroplated according to a method of the present invention and then treated to a double anneal process (easy-axis/hard-axis) as described herein is illustrated. The results show that both easy axis coercivity (Hce) and hard axis coercivity (Hch) are less than 2 Oe. Moreover, the film becomes almost magnetic isotropic in that the B—H loop along the easy axis is similar to that along the hard axis. Another advantage of the double annealing process is a lowering of the anisotropy field (Hk) to less than 3 Oe. Note that there is no change in Bs for the CoFe magnetic layer during the double anneal process.
In a second embodiment, the soft magnetic layer is electroplated as described previously followed by a hard axis anneal and then with an easy-axis anneal. The length of each anneal step is between 20 and 300 minutes and is preferably greater than 30 minutes. The substrate is cooled between annealing steps as described previously. Similar to the first embodiment, the applied magnetic field may be kept constant during the two annealing steps or the applied field for the easy axis anneal may be unequal to that for the hard axis anneal step.
Referring to FIG. 5, a B—H loops plot is illustrated for a CoFe magnetic layer that has been electroplated according to a method of the present invention and then treated to a double anneal process (hard-axis/easy-axis) as described in the second embodiment. The results show that both easy axis coercivity (Hce) and hard axis coercivity (Hch) are less than about 2 Oe. The film is anisotropic but with a much smaller Hk of about 5 Oe compared with an as-plated 100 e. The magnetic properties are also improved compared with a hard-axis only anneal as shown in FIG. 3 b. The electroplated and double annealed CoFe or CoFe alloy film of the present invention exhibits superior soft magnetic characteristics which are suitable for implementing in a write head for high density and high frequency applications. A CoFe or CoFe alloy magnetic layer formed according to a method described herein enables the high frequency response of a recording head to be substantially improved.
The double anneal process of the present invention is especially suitable for improving the magnetic softness of electroplated CoFe or CoFe alloys. However, the double anneal process may also be applied to sputtered films but the improvement in magnetic properties is not as significant. Nevertheless, the Hce, Hch, and Hk values for a CoFe sputtered film may also be substantially lowered by applying a double anneal process as described herein. For example, the B—H loops of a sputter deposited Co₃₀Fe₇₀film is depicted in FIG. 6 a and has a Hce=30.5 Oe, Hch=8.2 Oe, and Hk=61 Oe. After a two step anneal process where an easy-axis anneal is followed by a hard-axis anneal according to an embodiment of the present invention, the B—H loops in FIG. 6 b indicate a substantial improvement in magnetic softness and lower anisotropy field. The results after the easy-axis anneal step are Hce=20 Oe, Hch=6.9 Oe, and Hk=38.2 Oe. Subsequently, when the hard-axis anneal step is completed, Hce drops to 15.8 Oe, Hch=7.8 Oe, and Hk is reduced to 21 Oe. Note that the initial Hce, Hch, and Hk values after sputter deposition of a CoFe magnetic layer are much higher than achieved by an electroplating process of the present invention. Even with the improvement in magnetic softness of the sputter deposited CoFe or CoFe alloy after double annealing, the magnetic layer still has a hardness too high for use in advanced recording heads that require optimum high frequency response.
The inventors emphasize that the combination of low coercivity, low Hk, and high Bs is best achieved with an electroplating method and a two step magnetic anneal process as described herein. Although the electroplating method or the double anneal process of the present invention are each capable of reducing Hce, Hch, and Hk in a magnetic layer, it is a combination of the two methods in a process sequence that delivers the ultimate improvement in magnetic performance which is required for advanced write heads. This outcome is an advantage over prior art in that conventional one step anneal processes are not capable of significantly reducing Hk and electroplating processes by themselves are not sufficient to produce a soft magnetic layer with high Bs necessary for high density and high frequency recording operations.
While this invention has been particularly shown and described with reference to, the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of this invention.

Claims

1. A method for forming a soft magnetic layer having a high saturation magnetization (Bs), comprising:

(a) electroplating a soft magnetic layer on a substrate, said soft magnetic layer has a first axis magnetization direction and a second axis magnetization direction wherein the first axis intersects the second axis;

(b) performing a first anneal step wherein a first magnetic field is applied along the first axis; and

(c) performing a second anneal step wherein a second magnetic field is applied along the second axis.

2. The method of claim 1 wherein the first axis is the easy axis and the second axis is the hard axis.

3. The method of claim 1 wherein the first axis is the hard axis and the second axis is the easy axis.

4. The method of claim 1 wherein said electroplating comprises an electroplating bath comprised of Fe⁺²ions, Co⁺²ions, boric acid, one or more aryl sulfinate salts, and said electroplating bath is maintained at a pH between about 2 and 3, and in a temperature range from about 10^OC to 25^OC.

5. The method of claim 4 wherein said electroplating further comprises applying a peak current density between about 30 and 60 mA/cm²during one or more cycles based on an “ON” time of about 10 to 50 ms and an “OFF” time of about 20 to 200 ms.

6. The method of claim 4 wherein said electroplating bath is comprised of ferrous sulfate at a concentration of about 50 to 140 g/L, cobalt sulfate at a concentration of about 20 to 70 g/L, boric acid at a concentration of about 20 to 40 g/L, sodium benzenesulfinate at a concentration of about 0.05 to 0.3 g/L, and is further comprised of nickel sulfate at a concentration of 0 to about 70 g/L, one or more electrolytes at a concentration of about 0.5 to 50 g/L, a surfactant at a concentration of 0 to about 0.15 g/L, and a stress reducing agent with a concentration of 0 to about 2 g/L.

7. The method of claim 1 wherein said first anneal step and said second anneal step are comprised of a temperature between about 180^OC and 250^OC for a period of about 20 to 300 minutes.

8. The method of claim 1 wherein the first magnetic field is between about 200 Oe and 300 Oe and the second magnetic field is between about 200 Oe and 300 Oe.

9. The method of claim 1 wherein said soft magnetic layer is CoFe, a CoFe alloy, NiFe, or a NiFe alloy.

10. The method of claim 1 wherein the soft magnetic layer has an easy axis coercivity (Hce) and a hard axis coercivity of about 2 Oe or less, an anisotropy field (Hk) of about 5 Oe or less, and a Bs of ≧24 kG.

11. The method of claim 1 wherein the soft magnetic layer is a pole layer in a write head.

12. A method for softening a magnetic layer on a substrate, said magnetic layer has a first axis magnetization direction and a second axis magnetization direction; comprising:

(a) performing a first anneal step wherein a first magnetic field is applied along the first axis; and

(b) performing a second anneal step wherein a second magnetic field is applied along the second axis.

13. The method of claim 12 wherein the soft magnetic layer is comprised of CoFe, a CoFe alloy, NiFe, or a NiFe alloy.

14. The method of claim 12 wherein the first axis is the easy axis and the second axis is the hard axis.

15. The method of claim 12 wherein first axis is the hard axis and the second axis is the easy axis.

16. The method of claim 12 wherein said first anneal step and said second anneal step are comprised of a temperature between about 180^OC and 250^OC for a period of about 20 to 300 minutes.

17. The method of claim 12 wherein the first magnetic field is between about 200 Oe and 300 Oe and the second magnetic field is between about 200 Oe and 300 Oe.

18. The method of claim 12 wherein the soft magnetic layer is a pole layer in a write head.

19. The method of claim 16 wherein the substrate is cooled between the first anneal step and the second anneal step.

20. The method of claim 12 wherein easy axis coercivity (Hce), hard axis coercivity (Hch), and anisotropy field (Hk) are all substantially reduced compared to the magnetic layer properties prior to the double annealing process.