JPH02304708A - Magneto-resistance effect type head - Google Patents

Abstract

PURPOSE:To obtain an MR head where a suitable bias level is impressed with a small bias current by laminating a ferro-magneto-resistance effect element and a non-crystal soft magnetic substance layer through a non-magnetic conductor layer and composing the non-crystal soft magnetic substance layer with the material which defines Co, Ta and Mo as main components. CONSTITUTION:As the non-crystal soft magnetic substance layer, a CoTaMo film layer 7 (82%Co-6%Ta-12%Mo, atom %) is filmed on a non-magnetic conduc tor layer 2. Afterwards, a photo-regist pattern in a prescribed shape is formed on a laminated body 2 and ion etching is executed in a gaseous Ar atmosphere. Then, the laminated body is worked to a rectangular pattern. Next, a terminal 6 is formed to supply a sense current I to the laminated body and the MR head is prepared. Namely, when the CoTaMo film is used as the non-crystal soft magnetic substance layer 5, the satisfactory bias level, for which a bias angle is made almost 45 deg., can be obtained. Thus, the MR head for which the suitable bias level is impressed even by the small bias current and which is provided with satisfactory linear response and high reproducing efficiency can be obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a ferromagnetic magnetoresistive element (hereinafter referred to as an MR element) that reads magnetic information written into a magnetic storage medium using the magnetoresistive effect. The present invention relates to a magnetoresistive head (hereinafter abbreviated as MR head) equipped with a magnetoresistive head (hereinafter abbreviated as MR head).

[Prior Art] As is well known, when an MR element is used as a highly efficient reproducing Furukawa magnetic head that has a linear response to magnetic information written on a magnetic storage medium, the sense flowing through the MR element is used. The angle θ (hereinafter referred to as bias angle) formed by the current I and the magnetization M of the MR element is set to a predetermined value (preferably 45 degrees).
Bias means shall be provided to set the

Various methods have been disclosed as the above-mentioned bias means, but among these, the MR head disclosed in Utility Model Application No. 51048201 uses a nonmagnetic conductor layer and an amorphous soft magnetic material on the MR element. It has been shown that an excellent bias angle θ can be obtained by a structure in which layers are sequentially laminated, and an MR head with excellent linear response can be realized.

That is, as shown in FIG. 4, M made of a ferromagnetic thin film is deposited by sputtering or vapor deposition on an insulating substrate (not shown) with a smooth surface made of glass, ferrite, etc.
An R element 1 (for example, a NiFe alloy with a film thickness of 200 to 500) is formed, and Ti, Mo, Cr,
A non-magnetic conductor layer 2 such as 'la, W, etc. is formed in the same manner,
Furthermore, an MR head having a structure in which an amorphous soft magnetic layer 5 is formed on the nonmagnetic conductor layer 2 by a similar method is disclosed.

Here, reference numeral 6 denotes a terminal for supplying current to the laminate of the MR element 1, the nonmagnetic conductor layer 2, and the amorphous soft magnetic layer 5.

In such an MR head, the sense current I supplied from the terminal 6 is branched not only to the MR element 1 but also to the nonmagnetic conductor layer 2 and the amorphous magnetic layer 5. Therefore, in such a structure, the sense current (IV) shunted to the MR element 1 and the non-magnetic conductor layer 2 generates a magnetic field that passes within the plane of the amorphous soft magnetic layer 5 and in a direction perpendicular to the direction of the sense current I. is generated, and this magnetic field rotates the magnetization direction of the amorphous soft magnetic layer 5. Therefore, the magnetization in the amorphous soft magnetic layer 5 generates a magnetic field around the amorphous soft magnetic layer 5 in a direction opposite to the direction of the magnetization, a part of which is applied to the MR element 1. . On the other hand, amorphous soft magnetic material Figure 5 and non-magnetic conductor H
2, a magnetic field is generated in the plane of the MR element 1 in a direction perpendicular to the sense current I, and the direction of this magnetic field is similar to that of the magnetic field generated by the magnetization of the amorphous soft magnetic layer 5 described above. Match the direction. In other words, the amorphous soft magnetic layer 5
A magnetic field generated by the magnetization and a magnetic field generated by the sense current I are applied to the fVIR element 1 as a bias magnetic field. This bias magnetic field rotates the magnetization of the MR element 1 with respect to the sense current I, and the bias angle θ of the MR element
is set to a predetermined value (ideally 45 degrees), and an MR head with excellent linear response is realized.

[Problems to be Solved by the Invention] By the way, in the MR head having the structure of (e) above, that is, the structure in which the MR element 1, the nonmagnetic conductor layer 2, and the amorphous soft magnetic layer 5 are laminated, the amorphous C0 as the soft magnetic layer 5
When Zr, CoZrNb, etc. are used, their anisotropic magnetic field Hk is large, so the normal sense current range (5 to 2
0 mA>, the magnetization direction of the amorphous soft magnetic layer 5 did not rotate sufficiently, and a good bias level could not be achieved. For this reason, there is a problem (1) in that the linear response of the MR head is impaired and the reproduction efficiency is reduced.

On the other hand, one way to use an amorphous material with a large anisotropic magnetic field (-1) as the amorphous soft magnetic layer 5 and to achieve a good bias level is to increase the value of the sense current. Conceivable. However, this increases heat generation due to the sense current, causes thermal drift in the electrical resistance of the MR element and thermal noise, and impairs the characteristics of the MR head. In addition, disconnections due to heat generation sometimes occurred, impairing the reliability of the device.

Furthermore, after forming the amorphous soft magnetic material that will become the amorphous soft magnetic layer 5, heat treatment may be performed while applying a magnetic field in the difficult axis direction to weaken the anisotropic magnetic field 1-1k. , since the heat treatment is performed in a magnetic field, the NiF that becomes the MR element
There was a problem in that magnetic dispersion occurred in the e-film and Barkhausen noise increased. In addition, MR during heat treatment
There is also the problem that mutual diffusion occurs between the elements 1, the nonmagnetic conductor layer 2, or the amorphous soft magnetic layer 5, and the magnetic properties of the MR element 1 or the amorphous soft magnetic layer 5 deteriorate.

Therefore, the magnetization rotates in the range of the normal sense current (5 to 2 mA), and in order to provide a sufficient bias level to the M and R elements 1, a soft magnetic material with a small anisotropic magnetic field (-1k) is used. It is important to use it as the amorphous soft magnetic layer 5 in order to essentially solve the above-mentioned problems.

The present invention has been made in response to the conventional circumstances as described above, and an object of the present invention is to provide an MR head in which an appropriate bias level can be applied with a small bias current.

[Means for Solving the Problems] The present invention provides a structure in which a ferromagnetic magnetoresistive element and an amorphous soft magnetic layer are laminated with a nonmagnetic conductive layer interposed therebetween, and the amorphous soft magnetic layer is made of Co. , Ta and lvl.

This is a magnetoresistive head characterized by being made of a material whose main component is

[Operation] FIG. 2 is a diagram showing the results of a computer simulation showing the relationship between the bias level of the MR head according to the present invention and the anisotropic magnetic field Hk of the soft magnetic material forming the amorphous soft magnetic layer. Here, the value of the sense current is 10 m8, the film thickness of the MR element is 400 emu/c, and the saturation magnetization MS is 800 emu/c.
c, anisotropic magnetic field Hk is 40e, specific resistance ρ is 20μΩ・c
m, the resistance change rate Δρ/ρ was 2%, the thickness of the nonmagnetic conductor layer was 200, and ρ was 50 μΩ·cm. In addition, the thickness of the amorphous soft magnetic layer is 300 mm, and the saturation magnetization MS is 80 mm.
0 emu/cc, and the specific resistance ρ was 100 μΩ·cm. Furthermore, the definition of bias level is, as shown in FIG. 3, the maximum resistance change ΔRmax when an external magnetic field 10 of 10 which is sufficient to saturate the MR element is applied, and
It was taken as the ratio of the difference ΔR in resistance when the external magnetic field is O and when an external magnetic field of ±Ho is applied. That is, bias level=ΔR/ΔRmax.

As is clear from Figure 2, the value of the anisotropic magnetic field Hk is 8.
It can be seen that above 0e, the bias level becomes about 0.6 or above, and an inappropriate bias is applied to the MR element. When the anisotropic magnetic field Hk of the amorphous soft magnetic material forming the amorphous soft magnetic layer is less than 80e, the bias level is approximately constant and exhibits an ideal value of about 0.5. Therefore, by setting the anisotropic magnetic field Hk of the amorphous soft magnetic material to less than 80e, an MR head having a highly linear response and reproduction efficiency can be obtained by 1q.

Referring to the above simulation results, the present inventors thinned various Co-metallic amorphous soft magnetic materials by vapor deposition or sputtering, and applied the anisotropic magnetic field Hk to VSM (vibrating sample magnetic field). As a result of measurement using B-H Curve I/C1NO, the results shown in Table 1 were obtained.

Table 1 As shown in Table 1, an anisotropic magnetic field of 4 to 60 e is applied to 1 q in the COTaMo amorphous material, which satisfies the simulation results shown in FIG. 2. In other words,
By using the COTaMo film as the amorphous soft magnetic material@5, a good bias level with a bias angle of approximately 45 degrees can be obtained, and MR/@D with high reproduction efficiency can be realized.

[Example] Next, an example of the present invention will be described with reference to the drawings.

Example 1 FIG. 1 is a configuration diagram of an embodiment of the present invention.

In FIG. 1, the MR element 1 is formed by using a vapor deposition method on a non-magnetic substrate (not shown) such as glass, and the film thickness is 400 mm. A alloy (82% Ni-18% Fe, 1% Φ) film was formed. Note that during the deposition, a magnetic field of 1000 e was applied using a permanent magnet to impart uniaxial anisotropy to the permalloy film. Then,
The thickness of the non-magnetic conductor layer 2 is 200 mm using the same vapor deposition method.
A Ti film was formed on the permalloy film. Furthermore, as an amorphous soft magnetic layer, a film thickness of 300 mm and an anisotropic magnetic field of 1-
1 to 50e CoTaMo film layer 7 (Co 82%-1
-A6%-Mo12%, J-Oji%) was formed into a film on the Ti film of the previous J-ho using a vapor deposition method. After that, a four-dimensional resist pattern with a predetermined shape is formed on this laminate, and ion etching is performed in a △r gas atmosphere.
It was processed into a rectangular pattern of μ7+1.

Here, the etching conditions are: acceleration voltage: 500V;
A r 1 soil crab 0.1 mrorr.

Next, a terminal 6 is connected to supply the sense current I to the above-mentioned stacked body.
was formed using integrated thin film technology to produce an MR head. In addition, the terminal 6 uses a laminated vapor deposited film of Oi and AU,
The film thickness was 0.5 μmC for 50 people each.

In the tVIR head according to this embodiment having the above-described configuration, the sense current I is 5 to 15...AFMR element 1.
It was confirmed that the bias angle θ could be set to approximately 45 degrees, and an MR head with good linear response and high reproduction efficiency was realized.

In addition, in the above embodiment, only the example in which the MR element, the nonmagnetic conductor layer, and the COTaMo film layer are laminated in this order has been mentioned, but it is also possible to laminate in the order of the Co-O-Al-AMo film layer, the nonmagnetic conductor layer, and the MR element. The MR head also exhibited excellent linear response and high reproduction efficiency. Furthermore, the material forming the nonmagnetic conductor layer is not limited to Ti, for example, T.
a, MolW, or an alloy thereof may be used. Furthermore, the composition of the CoTaMo film in the examples is just an example, and other compositions may be used depending on the structure, specifications, etc. of the applied MR head. Of course, in this case, CoZrM
Needless to say, the composition does not deteriorate the magnetic properties of the O film, especially the anisotropic magnetic field 1k. In addition, Co, as long as it does not deteriorate the magnetic properties, especially the anisotropic magnetic field Hk,
There is no problem even if Ta and MoO40 elements are added to the CoTaMo film.

Comparative Example 1 Amorphous soft magnetic layer with a thickness of 300 mm and an anisotropic magnetic field Hk i
An MR head was manufactured in the same manner as in the example except that a 60e C0Zr layer was used. In this MR head,
Even if a sense current of about 35 to 40 mA is passed, a sufficient bias is not applied to the MR element, and the reproduction efficiency is about 30 to 50% lower than the MR head according to the present invention, making it impossible to put it into practical use. It became clear.

Moreover, amorphous soft magnetic materials having a large anisotropic magnetic field Hk, namely COTr, coHt, c.

Even in the MR head using ZrNb, COZrHf, or CoZrTi as the amorphous soft magnetic layer, a sufficient bias level could not be obtained and the reproduction efficiency was low, similar to the MR head of this comparative example.

[Effects of the Invention] As described above, according to the present invention, an appropriate bias level can be applied even with a small bias current of about 15 mA, and an MR head with excellent linear response and high reproduction efficiency can be realized.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an embodiment of the present invention, and Figure 2 is MR/\
A characteristic diagram showing the relationship between the bias level of the magnet and the anisotropic magnetic field of the soft magnetic material forming the amorphous soft magnetic layer. Figure 3 is an explanatory diagram for explaining the bias level. Figure 4 is MR.
FIG. 3 is an explanatory diagram for explaining a head. 1...MR element 2...Nonmagnetic conductor layer 5...Amorphous soft magnetic layer 6...Terminal 7-COT a MO film layer

Claims (1)

[Claims] (1) A ferromagnetic magnetoresistive element and an amorphous soft magnetic layer are laminated with a nonmagnetic conductive layer interposed therebetween, and the amorphous soft magnetic layer is made of a material containing Co, Ta, and Mo as main components. A magnetoresistive head characterized by comprising: