JPH08147637A - Magnetoresistance magnetic head - Google Patents

Abstract

PURPOSE: To realize an MR head by which the symmetry of a reproduced signal is good and whose reproduction output is large. CONSTITUTION: In an MR head, a nonmagnetic layer and a magnetic layer are laminated on a yoke 1 so as to form an artificial-lattice magnetoresistance film 2. The MR head is completed by forming an electrode next to the artificial lattice film 2. Then, when a sense current I is made to flow, a magnetic field H in a magnetic medium 5 can be read out as a signal. In the MR head, the yoke 1 is used also as one magnetic layer out of two or more magnetic layers which sandwich the yoke 1. Since the yoke 1 is large as compared with the size of the artificial lattice film 2, the influence of magnetostatic coupling at the film end of the artificial lattice film 2 can be reduced. Thereby, it is possible to realize the head whose output is large and which is excellent in the symmetry of a reproduced signal waveform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resistance effect type magnetic head for reading a signal magnetic field recorded on a magnetic medium,
In particular, the present invention relates to a magnetoresistive effect magnetic head using an artificial lattice magnetoresistive effect film composed of two or more magnetic layers sandwiching a non-magnetic layer.

[0002]

2. Description of the Related Art In recent years, magnetic sensors have been made highly sensitive and magnetic recording has been made highly dense, and accordingly, magnetoresistive effect magnetic sensors (hereinafter referred to as MR sensors) and magnetoresistive effect magnetic heads. Development of (hereinafter referred to as MR head) has been actively pursued. The MR sensor and the MR head read the external magnetic field signal due to the resistance change of the reading sensor section made of a magnetic material. However, since the relative speed with the recording medium does not depend on the reproduction output, the MR sensor has high sensitivity. The MR head has a feature that a high output can be obtained even in high density magnetic recording.

Recently, an artificial lattice magnetoresistive film has been announced which is composed of two or more magnetic thin films sandwiching a non-magnetic layer and exhibits a large magnetoresistive change in an external magnetic field (Phys. Rev. Lett. ) Vol. 61, p. 2472, 1
988). Since this artificial lattice magnetoresistive film exhibits a large resistance change rate of several to several tens of percent due to an external magnetic field, a highly sensitive and high output MR head using an artificial lattice film has been proposed. Further, in the hard disk drive using the MR head as described above, the densification and miniaturization are progressing, and along with this, the magnetic signal area read / written on the medium is becoming smaller. Along with this, the track width of the MR head for reading this signal becomes smaller, and the size of the magnetoresistive film becomes smaller.

However, in the above artificial lattice magnetoresistive effect film, the magnetic layers are bonded to each other with the non-magnetic layer sandwiched therebetween, and the effect of the magnetostatic coupling is relative as the size of the film becomes smaller. Will grow larger. Magnetostatic coupling works so that the magnetization directions of the magnetic layers are anti-parallel, and the magnetization rotation of the magnetic layer due to the magnetic field from the medium does not occur at the film edge, so that the size of the artificial lattice magnetoresistive effect film decreases. ,
The reproduction output of the MR head becomes small.

[0005]

As described above, in the MR head using the artificial lattice magnetoresistive effect film, the influence of magnetostatic coupling between the magnetic layers at the artificial lattice film end or the sense current flowing in the film. Due to the influence of the current magnetic field due to, the magnetization directions of the adjacent magnetic layers are not sufficiently parallel or antiparallel,
There is a problem that the reproduction signal from the magnetic medium has poor waveform symmetry and the reproduction output does not become so large.
The present invention has been made to solve the above problems,
An object of the present invention is to provide an MR head having an artificial lattice magnetoresistive effect film in which the influence of magnetostatic coupling at the film edge is small, so that the reproduced signal has good symmetry and the reproduced output is large.

[0006]

According to the present invention, a yoke made of a magnetic material, a non-magnetic layer and a magnetic layer formed on a part of the yoke such that the film surface is parallel to the magnetic field of the magnetic medium. A layer, and the yoke is also used as one magnetic layer of the artificial lattice magnetoresistive effect film. In addition, a yoke made of a magnetic material having a gap, a non-magnetic layer and a magnetic layer formed on a part of the yoke such that the film surface is parallel to the magnetic field of the magnetic medium, and the circumference of the yoke. A recording inductive head, and a reproducing magnetoresistive head having a yoke also serving as one magnetic layer of the artificial lattice magnetoresistive film. It is to share the York.

Further, a single pole type yoke for perpendicular magnetic recording made of a magnetic material, a non-magnetic layer formed on a part of the yoke so that the film surface is parallel to the magnetic field of the magnetic medium, and It has a magnetic layer and a coil wound around a yoke for passing a recording signal current, and also serves as an inductive head for perpendicular magnetic recording and the yoke as one magnetic layer of the artificial lattice magnetoresistive effect film. The yoke is shared with the magnetoresistive head for reproduction.

[0008]

According to the present invention, the yoke is also used as one magnetic layer of the artificial lattice magnetoresistive effect film by forming the non-magnetic layer and the magnetic layer on a part of the yoke. It is possible to reduce the influence of magnetostatic coupling at the film edge of the film and the sense current magnetic field. Further, by providing a non-magnetic layer and a magnetic layer formed on a part of the yoke and a coil wound around the yoke, the inductive head for recording and the magnetoresistive head for reproducing are provided with a yoke. And the gap is shared. Further, by providing a non-magnetic layer and a magnetic layer formed on a part of a single pole type yoke for perpendicular magnetic recording, and a coil wound around the yoke, an inductive head for perpendicular recording and a reproducing The yoke is shared with the magnetoresistive head for use.

[0009]

1 is a schematic sectional view of an MR head showing an embodiment of the present invention, and FIGS. 2 and 3 are detailed sectional views of an artificial lattice magnetoresistive film formed on a yoke of the MR head. . In FIG. 1, 1 is NiFe, NiFeCo, FeA so that the signal magnetic field of the magnetic medium 5 can be detected with high sensitivity.
The MR head yoke 2 made of a soft magnetic material such as 1Si is formed on a part of the yoke 1 such that the film surface is parallel to the magnetic field of the magnetic medium 5, for example, 2 μm.
The artificial lattice magnetoresistive film 3 having an area of × 2 μm is the gap of this MR head.

2 and 3, 21 is a non-magnetic layer made of Cu or the like, 22 is a magnetic layer made of NiFe or the like, and 23 is F.
An antiferromagnetic layer made of eMn or the like, 24 an atomic layer made of a ferromagnetic material such as Co having a thickness of 5 to 10 angstroms, 2
5 is a high resistivity magnetic layer made of a material having a high resistivity such as Fe2 O3, 26 is a soft magnetic layer made of NiFe, and 27 is C
It is a high coercive force ferromagnetic layer made of o or the like.

In the MR head of this embodiment, a plurality of films are sequentially laminated on the yoke 1 (left in FIGS. 1 to 3), and the MR head shown in FIG.
The artificial lattice magnetoresistive effect film 2 having any one of the structures shown in FIG.

The magnetic material used in the magnetic layer of this embodiment is Fe, Ni, Co, Mn, Cr, Dy, Er, N.
d, Tb, Tm, Ge, Gd and the like are preferable. Examples of alloys and compounds containing these elements include Fe-S
i, Fe-Ni, Fe-Co, Fe-Gd, Ni-Fe
-Co, Ni-Fe-Mo, Fe-Al-Si (sendust), Fe-Y, Fe-Mn, Cr-Sb, Co-based amorphous, Co-Pt, Fe-Al, Fe-C, Mn.
-Sb, Ni-Mn, Co-O, Ni-O, Fe-O,
Ni-F, ferrite and the like are preferable.

The upper limit of the film thickness of each magnetic layer is 200 Å. On the other hand, the lower limit of the thickness of the magnetic layer is not particularly limited, but if it is 4 angstroms or less, the Curie point becomes lower than room temperature, which makes it impractical. Further, when the film thickness is 4 angstroms or more, it becomes easy to keep the film thickness uniform, and the magnitude of saturation magnetization does not become too small.
Even if the film thickness is set to 200 angstroms or more, the effect does not decrease, but the effect does not increase as the film thickness increases, and it is wasteful in manufacturing the film, which is uneconomical.

Since the magnetic characteristics of the magnetic layer existing in the magnetoresistive effect element cannot be directly measured, it is usually measured as follows. The magnetic thin film to be measured is alternately deposited with the non-magnetic thin film until the total thickness of the magnetic thin film reaches about 200 to 400 angstroms to prepare a measurement sample, and the magnetic characteristics of the sample are measured.
In this case, the thickness of the magnetic layer, the thickness of the non-magnetic layer and the composition of the non-magnetic layer are the same as those in the magnetoresistive effect measuring element.

The non-magnetic layer 21 is a material that plays a role of weakening the magnetic interaction between the magnetic layers, and the kind thereof is not particularly limited, and may be appropriately selected from various metals or semi-metal non-magnetic materials and non-metal non-magnetic materials. Good. As a metal non-magnetic material,
Au, Ag, Cu, Pt, Al, Mg, Mo, Zn, N
b, Ta, V, Hf, Sb, Zr, Ga, Ti, Sn,
Pb and the like and alloys thereof are preferable. As the semi-metal non-magnetic material, SiO2, SiO, SiN, Al2 O3, Zn
O, MgO, TiN and the like, and those obtained by adding another element to these are preferable.

The thickness of the nonmagnetic layer 21 is preferably 50 angstroms or less. Generally, when the film thickness exceeds 50 Å, the resistance is determined by the non-magnetic layer, and the spin-dependent scattering effect becomes relatively small, resulting in a small magnetoresistance change rate. On the other hand, when the film thickness is 4 angstroms or less, the magnetic interaction between the magnetic layers becomes too large, and the occurrence of a magnetic direct contact state (pinhole) is unavoidable. It becomes difficult for the magnetization directions of both magnetic layers to become antiparallel.

The film thickness of the magnetic layer or the non-magnetic layer can be measured by a transmission electron microscope, a scanning electron microscope, Auger electron spectroscopy or the like. The crystal structure of the thin film is
It can be confirmed by X-ray diffraction or high-speed electron diffraction.

Next, the structure of the artificial lattice magnetoresistive film 2 shown in FIGS. 2 and 3 will be described. Artificial lattice film 2 of FIG.
Is what is called a spin valve. this is,
When the antiferromagnetic layer 23 made of FeMn or the like is formed on the magnetic layer 22 made of NiFe or the like, the magnetization curve of the magnetic layer 22 is translated by the exchange coupling magnetic field Hex, and the magnetization of the yoke 1 is changed between the zero magnetic field and Hex. Magnetic layer 22 exchange coupled with orientation
A large resistance change rate can be obtained by making the magnetization directions of 1 and 2 antiparallel.

In the example of FIG. 2A, NiFe and NiFe are used.
On the yoke 1 made of a soft magnetic material such as Co or FeAlSi, a non-magnetic layer 21 made of Cu, Au, Ag, or an alloy thereof, a magnetic layer 22 made of NiFe, NiFeCo, Co, FeMn, NiMn, NiO. The magnetic layer 22 is exchange-coupled with the antiferromagnetic layer 23 by sequentially stacking the antiferromagnetic layers 23 made of, for example. In the example of FIG. 2B, in the structure of FIG. 2A, a thin atomic layer 24 of 5 to 10 angstroms made of a ferromagnetic material such as Co is provided above and below the non-magnetic layer 21 to increase the resistance. The rate of change can be obtained.

In the example of FIG. 2C, the yoke 1 and the non-magnetic layer 2 are used.
1 and oxide ferromagnet Fe2O3, NiO, Co
High resistivity magnetic layer 2 made of O, CrO, etc., amorphous CoZrMo, etc., sendust FeAlSi, etc.
5. By stacking the soft magnetic layer 26, the sense current flowing in the artificial lattice magnetoresistive film is prevented from flowing into the yoke 1 and the resistance value of the artificial lattice film is not lowered.
In this case, the yoke 1 and the magnetic layers 25 and 26 are ferromagnetically coupled and the magnetization is inverted by the same external magnetic field. In addition, the magnetic layer 2
Similar effects can be obtained even if 5, 26 are provided between the yoke 1 and the atomic layer 24 in the configuration of FIG.

In the artificial lattice magnetoresistive film 2 of FIG. 3, a non-magnetic layer is formed between two types of magnetic layers having different coercive forces, a yoke 1 made of a soft magnetic material having a small coercive force and a magnetic layer 27 having a large coercive force. Layers 21 are stacked. This is because a large resistance change rate is obtained by reversing the magnetization directions of the two types of magnetic layers in parallel and antiparallel.

In the example of FIG. 3A, Cu,
Nonmagnetic layer 2 made of Au, Ag, or an alloy thereof
1, a high coercive force ferromagnetic layer 27 made of Co or the like is laminated. In the example of FIG. 3B, in the configuration of FIG.
Under the non-magnetic layer 21, 5 to 10 made of a ferromagnetic material such as Co
By providing the atomic layer 24 having a thin angstrom, a larger rate of resistance change can be obtained.

In the example of FIG. 3C, the yoke 1 and the non-magnetic layer 2 are used.
1 and the high specific resistance magnetic layer 25 similar to that of FIG.
By stacking the soft magnetic layer 26, the sense current does not flow into the yoke 1 and the resistance value of the artificial lattice film is not lowered. Also in this case, the yoke 1 and the magnetic layer 2
Nos. 5 and 26 are ferromagnetically coupled and the magnetization is inverted by the same external magnetic field. Also, the same effect can be obtained by providing the magnetic layers 25 and 26 between the yoke 1 and the atomic layer 24 in the configuration of FIG.

An MR head is completed by forming electrodes (not shown in FIG. 1) beside the artificial lattice magnetoresistive effect film 2 having the above-mentioned structure. In this MR head, when a sense current I flows in the direction perpendicular to the paper surface as shown in FIG. 1, the electric resistance changes due to the magnetic field H of the magnetic medium 5 passing through the yoke 1, so the magnetic field of the magnetic medium 5 is read as a signal. be able to.

In this MR head, the yoke 1 is also used as one magnetic layer of two or more magnetic layers sandwiching the nonmagnetic layer. At this time, since the size of the yoke 1 is larger than the size of the artificial lattice magnetoresistive effect film 2, even if the artificial lattice film 2 is processed into a fine shape, the magnetostatic force at the film end of the artificial lattice film 2 is reduced. The effect of coupling can be reduced. Further, the absolute value of the current magnetic field due to the sense current remains the same as before, but the influence is relatively small due to the magnetic layer (yoke 1) larger than before. As a result, an MR head having a large reproduction output and excellent symmetry of the reproduction signal waveform can be realized.

FIG. 4 is a schematic sectional view of an MR head showing another embodiment of the present invention. FIG. 4 (a) is a head for horizontal magnetic recording / reproducing, and FIG. 4 (b) is a perpendicular magnetic recording / reproducing. It is an example of a head for. 1a is a yoke similar to the example of FIG. 1 and 1b
Is a single pole type yoke for perpendicular magnetic recording made of a soft magnetic material such as NiFe, NiFeCo, or FeAlSi, and 4 is a coil for passing a recording signal current.
5 is a bird's-eye view of the MR head of FIG. 4 (a) seen obliquely from above. 10 is an electrode connected to the artificial lattice magnetoresistive film 2, and 11 is an electrode connected to the coil 4. .

The structures of the yoke 1a, the gap 3, the artificial lattice magnetoresistive film 2 and the electrode 10 in the examples of FIGS. 4 (a) and 5 are the same as those of the example of FIG. 1, and a coil 4 is provided around the yoke 1a. Is provided. In this way, this MR head functions as a reproducing head similar to that shown in FIG. 1, and writes the signal magnetic field generated from the gap 3 in the magnetic medium 5 by passing a signal current through the coil 4, which is based on the conventional electromagnetic conversion principle. It can function as the used inductive head for recording.

That is, in this head, since the yoke 1 and the gap 3 are shared by the recording inductive head and the reproducing MR head, there is good track deviation between the inductive head and the MR head due to the skew angle. The head can be realized.

The structure of the artificial lattice magnetoresistive effect film 2 of FIG. 4 (b) is similar to that of the example of FIG. 1, and the coil 4 is wound around the yoke 1b as shown in FIG. 4 (a). It is the same. Thus, the head of FIG. 4 (b) functions as an inductive head for perpendicular magnetic recording in which the signal magnetic field generated between the upper and lower ends of the yoke 1b is written in the magnetic medium 5 by passing a signal current through the coil 4. In addition, it can function as a reproducing MR head whose electric resistance is changed by the magnetic field H of the magnetic medium 5 passing through the yoke 1.

That is, in this head, since the yoke 1b is shared by the recording inductive head and the reproducing MR head, it is possible to realize a good head with no track deviation between the inductive head and the MR head due to the skew angle. it can.

[0031]

According to the present invention, since the nonmagnetic layer and the magnetic layer are formed on a part of the yoke, the yoke is also used as one magnetic layer of the artificial lattice magnetoresistive effect film.
Even if the artificial lattice magnetoresistive effect film is processed into a fine shape, it is possible to reduce the effects of magnetostatic coupling and the sense current magnetic field at the film edge of the artificial lattice magnetoresistive effect film, resulting in a large reproduced output and a reproduced signal waveform. It is possible to realize a magnetoresistive effect type magnetic head having excellent symmetry.

Further, by providing a non-magnetic layer and a magnetic layer formed on a part of the yoke and a coil wound around the yoke, a magnetoresistive head having the above effect can be realized. In addition, since the yoke and the gap are shared by the inductive head for recording and the magnetoresistive head for reproducing, the recording head and the reproducing head are integrated at a low cost and highly reliable. It is possible to realize a horizontal magnetic recording / reproducing head in which there is no track deviation between the reproducing head and the reproducing head.

Further, by providing a non-magnetic layer and a magnetic layer formed on a part of a single pole type yoke for perpendicular magnetic recording, and a coil wound around the yoke, the above effect is obtained. It is possible to realize a magnetoresistive head, and since the yoke is shared by the inductive head for recording and the reproducing magnetoresistive head, the recording head and the reproducing head are integrated at a low cost. It is possible to realize a head for perpendicular magnetic recording / reproduction that is highly reliable and has no track deviation between the recording head and the reproducing head.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an MR head showing an embodiment of the present invention.

2 is a detailed cross-sectional view of an artificial lattice magnetoresistive effect film formed on a yoke of the MR head of FIG.

3 is a detailed sectional view of an artificial lattice magnetoresistive effect film formed on a yoke of the MR head of FIG.

FIG. 4 is a schematic cross-sectional view of an MR head showing another embodiment of the present invention.

5 is a bird's-eye view of the MR head of FIG. 4 (a) as seen from diagonally above.

[Explanation of symbols]

1, 1a, 1b ... Yoke, 2 ... Artificial lattice magnetoresistive effect film, 3 ... Gap, 4 ... Coil, 5 ... Magnetic medium.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kunihiko Ishihara 5-7-1, Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Katsutoshi Tagami 5-7-1, Shiba, Minato-ku, Tokyo Inside NEC Corporation

Claims (3)

[Claims] 1. A magnetoresistive effect magnetic head using an artificial lattice magnetoresistive effect film comprising two or more magnetic layers sandwiching a non-magnetic layer, wherein a yoke made of a magnetic material and a part of the yoke are provided on the yoke. It has a non-magnetic layer and a magnetic layer formed so that the film surfaces are parallel to the magnetic field of the magnetic medium, and the yoke is also used as one magnetic layer of the artificial lattice magnetoresistive effect film. Magnetoresistive magnetic head. 2. A magnetoresistive effect magnetic head using an artificial lattice magnetoresistive effect film composed of two or more magnetic layers sandwiching a non-magnetic layer, and a yoke made of a magnetic material having a gap, and this yoke. A non-magnetic layer and a magnetic layer formed on a part of the upper side of the magnetic medium so that the film surface is parallel to the magnetic field; and a coil wound around the yoke for flowing a signal current for recording. And a magnetoresistive head for reproducing, which shares a yoke with an inductive head for recording and a reproducing magnetoresistive head which also serves as one magnetic layer of the artificial lattice magnetoresistive film. head. 3. A magnetoresistive effect magnetic head using an artificial lattice magnetoresistive effect film composed of two or more magnetic layers sandwiching a non-magnetic layer, the single pole type yoke for perpendicular magnetic recording comprising a magnetic material. A non-magnetic layer and a magnetic layer formed on a part of the yoke such that the film surfaces thereof are parallel to the magnetic field of the magnetic medium; and a recording signal current wound around the yoke. And an inductive head for perpendicular magnetic recording, and a reproducing magnetoresistive head which also serves as one magnetic layer of the artificial lattice magnetoresistive film, and shares the yoke. Magnetoresistive effect magnetic head.