JPH09147325A - Magneto-resistive head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-resistive head (MR head) which is excellent in linear responsiveness and with which Barkhausen noises are suppressed by adopting a PtMn alloy which is an antiferromagnetic film having excellent corrosion resistance and capable of impressing a necessary and sufficient exchange anisotropic magnetic field in an extremely thin film. SOLUTION: This magneto-resistive head has a ferromagnetic material layer 3 exhibiting a magneto-resistance effect and an antiferromagnetic magnetic layer 4 coming into direct contact with this ferromagnetic layer 3. This antiferromagnetic material layer 4 consists of the PtMn alloy and is heat treated. The exchange anisotropic magnetic field is generated in this magnetic head at boundary with the ferromagnetic material layer 3 in direct contact with this layer. The film compsn. of the PtMn alloy is 5 to 54 Pt and 46 to 95at.% Mn. The heat treatment temp. thereof is in a range of 200 to 350 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Widely used are AMR heads and Spi.
The present invention relates to a magnetoresistive effect read head represented by an n-Valve head for ensuring linear response of the magnetoresistive effect and suppressing Barkhausen noise. The present invention relates to a magnetoresistive head that improves and effectively applies a bias by an exchange coupling magnetic field.

[0002]

2. Description of the Related Art As a conventional magnetoresistive read head (MR head), an AMR (Anisotropic Magnetoresistance) head using an anisotropic magnetoresistive effect phenomenon and a GMR (Gian) using a spin scattering phenomenon of conduction electrons are used.
t Magnetoresistance) head, and as one of GMR heads, a Spin that exhibits a high magnetoresistance effect in a low external magnetic field.
-Valve head is shown in U.S. Pat. No. 5,159,513.

1 and 2 are schematic diagrams of the AMR head element structure. For optimum operation of AMR head, AMR
Two bias fields are required for the ferromagnetic layer 3 (AMR material) to be effective. One bias magnetic field is A
This is because the resistance change of the MR material is made to respond linearly to the magnetic flux from the magnetic medium, and this bias magnetic field is perpendicular to the surface of the magnetic medium (Z direction in the figure) and to the film surface of the AMR material. Parallel. Usually, this bias magnetic field is called a lateral bias, and is obtained by arranging the soft magnetic material 1 formed through the electric insulating layer 2 in the vicinity of the AMR material and causing a detection current to flow from the conductive layer 5 to the MR element. You can

The other bias magnetic field is usually called a longitudinal bias magnetic field and is applied parallel to the film surface of the magnetic medium and the AMR material 3 (X direction in the figure). The purpose of the longitudinal bias magnetic field is to suppress Barkhausen noise caused by the AMR material 3 forming a large number of magnetic domains, that is, a noise-free smooth magnetic field from the magnetic medium.
This is in order to make the resistance change extremely.

In order to suppress Barkhausen noise, it is necessary to make the AMR material 3 into a single magnetic domain, and there are two methods of applying a longitudinal bias for that purpose. One is A
A method of using a leakage magnetic flux from the magnet 6 by arranging the magnets 6 on both sides of the MR material 3 and a method of using an exchange anisotropic magnetic field generated at a contact interface with the antiferromagnetic material layer 4 are another method. Is.

On the other hand, as shown in FIG. 3 and FIG.
For optimum operation of the −Valve head, in the sandwich structure of Free magnetic layer 7 / non-magnetic intermediate layer 8 / Pinned magnetic layer 9, bias is applied to the Free magnetic layer 7 in the track direction (X direction in the figure). The magnetization is directed in the track direction in a magnetic domain state, and the magnetization direction of the pinned magnetic layer 9 is the Z direction in the drawing, that is, the free magnetic layer 7
It is necessary to apply a bias in a direction orthogonal to the magnetization direction of the above, and to orient it in the Z direction in the figure in a single magnetic domain state. The magnetization direction of the Pinned magnetic layer 9 should not be changed by the magnetic flux from the magnetic medium (Z direction in the drawing), and the direction of the Free magnetic layer 7 should be 9 with respect to the magnetization direction of the Pinned magnetic layer 9.
A linear response of the magnetoresistive effect can be obtained by changing the range of 0 ± θ degrees.

The magnetization direction of the pinned magnetic layer 9 is represented by Z in the figure.
A relatively large bias magnetic field is required to fix the direction, and the larger the bias magnetic field, the better. A bias magnetic field of at least 1000e is required in order to overcome the demagnetizing field in the Z direction in the figure and prevent the magnetization direction from fluctuating due to the magnetic flux from the magnetic medium.

As a method for obtaining this bias magnetic field, there is usually a method of utilizing an exchange anisotropic magnetic field generated by bringing the diamagnetic layer 10 into contact with the pinned magnetic layer 9.

The bias applied to the free magnetic layer 7 is to secure a linear response and to suppress Barkhausen noise caused by the formation of a large number of magnetic domains. A method similar to the longitudinal bias in the AMR head, That is, the magnets 11 are arranged on both sides of the free magnetic layer 7 and
The method of utilizing the leakage magnetic flux from the and the method of utilizing the exchange anisotropic magnetic field generated at the contact interface with the antiferromagnetic material layer 13 are usually used.

As described above, the exchange anisotropic magnetic field generated at the contact interface with the antiferromagnetic film is used for the longitudinal bias of the AMR head, the bias of the Pinned magnetic layer and the bias of the Free magnetic layer of the Spin-Valve head. Thus, a magnetoresistive head having good linear response and suppressing Barkhausen noise can be realized.

The exchange anisotropic magnetic field is a phenomenon caused by exchange interaction between the magnetic moments of the ferromagnetic film and the antiferromagnetic film at the contact interface, and is a ferromagnetic layer such as NiFe.
Fe is used as an antiferromagnetic film that produces an exchange anisotropic magnetic field with the film.
Mn films are well known. However, the FeMn film has remarkably poor corrosion resistance, and there are problems that corrosion occurs during the magnetic head manufacturing process and operation of the magnetic head, the exchange anisotropic magnetic field significantly deteriorates, and the magnetic medium is damaged. It is known that the temperature near the FeMn film during the operation of the magnetic head rises to about 120 ° C. due to the heat generated by the detected current, but the exchange anisotropic magnetic field due to the FeMn film is sensitive to temperature changes. Since the exchange anisotropic magnetic field decreases almost linearly with respect to the temperature until it disappears (blocking temperature: Tb) at a temperature of about 150 ° C., there is a problem that a stable exchange anisotropic magnetic field cannot be obtained. .

As an invention improving the corrosion resistance and blocking temperature of the FeMn film, there is a NiMn alloy or a NiMnCr alloy having a face-centered tetragonal structure disclosed in, for example, JP-A-6-76247, and the corrosion resistance of the NiMn film is FeMn. Although better than the corrosion resistance of the film, it is not practically sufficient. The NiMnCr film is an alloy to which Cr is added in order to improve the corrosion resistance of the NiMn film. However, although the corrosion resistance is improved by adding Cr, there is a problem that the magnitude of the exchange anisotropic magnetic field and the blocking temperature are lowered.

In order to obtain an exchange anisotropic magnetic field in a NiMn alloy or a NiMnCr alloy, CuAg-I having a face centered tetragonal (fct) structure in a part of the antiferromagnetic film.
In order to obtain stable characteristics, the magnetic head manufacturing process must be performed because it is necessary to control the ordered-disordered transformation and the controlled volume ratio of the ordered phase and the ordered phase. Inevitably, the process control and management in will become very complicated. Further, in order to obtain the required exchange anisotropic magnetic field, the heat treatment in the magnetic field must be repeated a plurality of times and the cooling rate is gentle, for example from 255 ° C to 4 ° C.
17 HR up to 5 ° C (Appl. Phys. Lett.
65 (9), 29 August 1994) is also a problem in the manufacturing process.

As an invention for improving the blocking temperature of the FeMn film, a NiFe / FeMn laminated film is formed at 260 ° C.
Heat treatment is performed for 20 HR to 50 HR at a temperature of ~ 350 ° C, and the NiFe / FeMn interface is exposed to Ni by diffusion by the heat treatment.
A method of forming a --Fe--Mn ternary alloy layer is disclosed in US Pat.
As described in Japanese Patent No. 809109, it can be easily understood that it is not effective in improving the corrosion resistance, which is the biggest problem of the FeMn film, and the required heat treatment time is 20 HR
The extremely long length of 50 HR becomes a problem in the manufacturing process.

Further, in existing publications such as "Magnetic Handbook" published by Asakura Shoten, Mn is used as an antiferromagnetic material.
System alloys such as NiMn, PdMn, AuMn, PtM
Although materials such as n and RhMn3 are shown, there is no comment on the exchange anisotropic magnetic field at the contact interface with the ferromagnetic film, and the antiferromagnetic film is an ultrathin film with a thickness of several hundred angstroms. It is completely unknown about its own characteristics and the exchange anisotropic magnetic field.

[0016]

A first object of the present invention is to provide an antiferromagnetic film having excellent corrosion resistance and capable of applying a necessary and sufficient exchange anisotropic magnetic field in an ultrathin film. An object is to provide a magnetoresistive head (MR head) having excellent responsiveness and suppressing Barkhausen noise.

A second object is to provide an MR head having excellent linear response and suppressing Barkhausen noise by providing an antiferromagnetic film having a slow blocking temperature dependence of the exchange anisotropic magnetic field and having a high blocking temperature. It is to be.

A third object is to provide an antiferromagnetic film in which the heat treatment process for obtaining the above-mentioned various characteristics can be realized at the temperature, time and temperature decreasing rate used in the usual MR head manufacturing process. An object of the present invention is to provide an MR head having excellent linear response and suppressing Barkhausen noise.

[0019]

According to the present invention, in a magnetoresistive effect read head, the magnetoresistive effect exhibits a linear response to a magnetic flux from a magnetic medium and suppresses Barkhausen noise. An antiferromagnetic film in direct contact with the body film applies a necessary and sufficient bias magnetic field, and the antiferromagnetic film is a PtMn alloy,
After forming the ferromagnetic film that is in direct contact with the PtMn antiferromagnetic film, heat treatment is performed at a temperature of 200 ° C. to 350 ° C. at the interface with the ferromagnetic film that is in direct contact with the PtMn antiferromagnetic film. It is characterized in that a predetermined mutual diffusion layer is formed to generate an exchange anisotropic magnetic field.

This heat treatment can be achieved at the same temperature, holding time, and temperature rising / falling rate as the heat treatment performed in the usual magnetoresistive head manufacturing process, and is an extremely realistic heat treatment method.

Further, the PtMn alloy includes FeMn, NiMn,
Corrosion resistance is extremely superior to that of NiMnCr alloy, corrosion does not proceed even in various solvents and cleaning agents in the magnetoresistive head manufacturing process, and even in operation of the magnetoresistive head in a harsh environment, it is chemically resistant. Stable.

The exchange anisotropy field obtained by forming a predetermined interdiffusion layer at the interface between the PtMn antiferromagnetic film and the ferromagnetic film in direct contact is the exchange anisotropy due to the FeMn antiferromagnetic film. The magnetic field is extremely stable as compared with the magnetic field, and it can exhibit an exchange anisotropic magnetic field of a certain magnitude in the temperature range from room temperature, which is the operating temperature of the magnetoresistive head, to 120 ° C. It is characterized by being extremely stable within the operating temperature range. Furthermore, since the temperature at which the exchange anisotropic magnetic field disappears is extremely high at 380 ° C. as compared with 150 ° C. of the FeMn alloy, the exchange anisotropic magnetic field is generated during the magnetoresistive effect head manufacturing process and during the operation of the magnetoresistive effect head. It is extremely stable.

Further, the PtMn alloy can exhibit an exchange anisotropic magnetic field at both the upper and lower interfaces of the ferromagnetic film which is in direct contact with the PtMn alloy, and the crystal orientation required for obtaining the exchange anisotropic magnetic field with FeMn can be obtained. Since the exchange anisotropic magnetic field can be obtained without the underlying film such as the Ta film to be arranged, it is possible to realize an element structure which cannot be realized due to the limitation of the conventional method of using the antiferromagnetic film.

Further, the ferromagnetic film and the PtMn antiferromagnetic film are formed by the DC magnetron sputtering method, and the ferromagnetic film is thinned to obtain a large exchange anisotropic magnetic field. In addition, the heat treatment temperature of the annealing process can be lowered to the temperatures of the UV curing process and the hard baking process.

[0025]

5 to 22 show a first embodiment relating to the exchange anisotropic magnetic field obtained by the present invention. Pt
The exchange anisotropic magnetic field obtained by forming a predetermined interdiffusion layer at the interface between the Mn antiferromagnetic film and the ferromagnetic film in direct contact is the longitudinal bias in the AMR head of FIG. 1, S of FIG.
It can be used for the bias of the pinned magnetic layer 9 in the pin-valve head, the bias of the free magnetic layer 7 and the bias of the pinned magnetic layer 9 in FIG.

Film formation was performed by RF (Radio Frequency) conventional sputtering. The substrate is indirect water cooled and is not actively heated. 8 "φ size Ni80
Fe20, Co, Ta, Mn, Ni47Mn53 atom%
The film composition of the PtMn film was adjusted by appropriately arranging 10 mm square Pt pellets on the Mn target. The film composition of the NiMnCr film is Ni47Mn53.
The 10 mm square Cr and Mn pellets were appropriately placed on the target and adjusted. The film composition is about 2 μm on the Si substrate.
Was formed into a film and analyzed by XMA (X-ray microanalyzer). A glass substrate was used as the substrate for the magnetic property measurement and the corrosion resistance test. The sputtering power was 100 W and the sputtering gas pressure was 1 mTorr.
The get films were sequentially laminated one by one. About 50 by a pair of magnets placed on both sides of the glass substrate during film formation.
A unidirectional magnetic field of 0e was applied.

The heat treatment was performed in a vacuum of 5 × 10 to ⁶ Torr or less, and a unidirectional magnetic field of about 1000 Oe was applied. The temperature rising / falling rate of the heat treatment was fixed to 3 hours for each of temperature rising to a predetermined temperature and cooling from a predetermined temperature to room temperature. The predetermined temperature of the heat treatment was changed from 200 ° C. to 350 ° C., and the holding time at the predetermined temperature was 4 hours to 20 hours. P
The analysis of interdiffusion at the interface between the tMn antiferromagnetic film and the NiFe ferromagnetic film in direct contact was carried out by the depth profile by the Oger electron beam analysis. The film structure was analyzed by X-ray diffraction using a Co tube. The measurement of the exchange anisotropic magnetic field was obtained from the shift amount of the MH loop which is usually performed.

FIG. 5 shows the composition of the PtMn film as the Pt amount of 0 to 6
It is a measured value of a state immediately after film formation (as depo.) When changed to 0 atomic% (at%) and an exchange anisotropic magnetic field (Hex) after heat treatment at 270 ° C. for 9 hours. The film structure is Glass / Ta (100A) / NiFe (50A) /
It is PtMn (200A) / Ta (100A). The A represents angstrom.

The reason for forming Ta on the glass is Gl
This is to prevent the components on the ass and the NiFe film from interdiffusing by heat treatment. as depo. In the state of Pt, Hex is generated in the range of Pt amount of 0 to 21 at%.
Hex that can be observed substantially when the amount exceeds 21 at%
Does not occur. However, after the heat treatment, the Pt amount is 0 to 5
Hex occurs over the entire composition range of 4 at%, and especially Pt
The composition having an amount of 36 to 54 at% is as depo. Hex, which was not observed in the above, comes to be generated by the heat treatment, and the value thereof is a large value exceeding 200 Oe. Pt
A composition having an amount of 0 to 21 at% also has as depo. The value of the exchange anisotropy field after heat treatment is larger than that of

FIG. 6 shows changes in Hex when the heat treatment temperature is changed for a film having a Pt amount of 44 to 54 at%. Hold time at heat treatment temperature is 200 ° C, 230 °
C, 270 ° C for 9 hours, 250 ° C for 20 hours, 29
0 ° C., 330 ° C. and 350 ° C. are 4 hours, the temperature rising time to the heat treatment temperature is 3 hours, and the temperature lowering time is 3 hours. The film composition is Glass / Ta (100A) / NiFe
(75A) / PtMn (200A) / Ta (100A)
It is. Hex is not observed in the heat treatment at less than 200 ° C, but Hex begins to be observed in the heat treatment at 200 ° C or higher, and Hex is rapidly generated by the heat treatment at 230 ° C or higher. The amount is 44 ~
The film of 51 at% shows a large value of 200 Oe or more.

7 and 8 show the results of a more detailed examination of the heat treatment temperature and holding time dependence of Hex and the coercive force (Hc) at that time. The film composition is Glass / Ta (100
A) / NiFe (50A) / PtMn (200A) / T
a (100 A) and the film composition of PtMn is Pt47M
It is n53 at%. Focusing on 250 ° C. and 270 ° C., it can be seen that the value of Hex is larger as the holding time is longer.

As can be seen from the comparison between 20 hours at 250 ° C., 9 hours at 270 ° C. and 4 hours at 290 ° C.,
It can be seen that although the holding time becomes shorter as the temperature becomes higher, the value of Hex is the same or becomes larger in the high temperature heat treatment having the shorter holding time.

Hc has a temperature dependence tendency similar to that of Hex, and its value is also substantially equal to that of Hex. That is, the shape of the M-H loop at this time is such that the center is shifted by Hex in one direction of the H axis and the coercive force has substantially the same magnitude as the shift amount. Considering exchange anisotropy bias in AMR or Spin-Valve, the fact that both Hex and Hc are large means that the bias amount is large and stable, and thus He
It is preferable that both x and Hc are large.

The exchange anisotropic magnetic field is a physical phenomenon originated from exchange interaction between magnetic atoms at the interface between a ferromagnetic film and an antiferromagnetic film. The magnitude of Hex is long. Moreover, the fact that the higher the temperature at that time is, the larger it is that NiFe which generates an exchange anisotropic magnetic field by heat treatment.
It is suggested that some physical change is given to the interface between the film and the PtMn film, and the physical change becomes larger as the temperature is higher and the holding time is longer. This physical change,
The mechanism will be described later in detail.

FIG. 9 shows the relationship between Hex and the heat treatment temperature when the film thickness of the PtMn film is changed. Hold time is 200
° C, 230 ° C, 250 ° C for 9 hours, 270 ° C,
290 ° C. and 330 ° C. are 4 hours, and the temperature raising / lowering time is 3 hours each. The film composition is Glass / Ta (100
A) / NiFe (75A) / PtMn (XA) / Ta
(100 A), and the film composition of PtMn is Pt49Mn.
It is 51 at%. PtMn film thickness is 100, 200,
It can be seen that as the thickness increases to 300 A, Hex increases and the heat treatment temperature at which Hex begins to occur shifts to a low temperature. The results of further detailed examination of the film thickness dependence are shown in FIGS. 10, 11 and 12.

The film structure shown in FIG. 10 is Glass / Ta (10
0A) / NiFe (XA) / PtMn (300A) / T
a (100 A) and the film composition of PtMn is Pt49M
n51 at% and the heat treatment temperature is 250 ° C., 270
The temperature is changed to ° C, 290 ° C and 330 ° C.

The film structure shown in FIG. 11 is Glass / Ta (10
0A) / NiFe (XA) / PtMn (200A) / T
a (100 A), and the film composition of PtMn is the same as Pt.
It is 49 Mn 51 at%, and the same heat treatment as in FIG. 9 is performed.

In the film structure of FIG. 12, the film thicknesses of PtMn and NiFe are changed at the same time, and Glass / Ta (100
A) / NiFe (XA) / PtMn (XA) / Ta (1
00A), and the film composition of PtMn is as shown in FIGS.
Similarly to Pt49Mn51at%. Heat treatment is 29
It was performed by holding at 0 ° C for 4 hours. In each of FIGS. 9, 10, and 11, the temperature rising / falling time of the heat treatment is 3 hours.

As a result of FIGS. 9, 10, 11 and 12, H
It can be seen that the size of ex becomes larger as the film thickness of NiFe becomes thinner and becomes larger as the film thickness of PtMn becomes thicker. Regarding the film thickness of PtMn, the film thickness dependence is remarkable in the range of 100 A to 300 A, but the film thickness of 300 A to 5
In the range of 00A, there is not much film thickness dependency (Fig. 1
2). Therefore, it can be seen that a film thickness of PtMn of 300 A is sufficient.

On the other hand, regarding the film thickness of NiFe, it can be seen that Hex and film thickness are in an inversely proportional relationship. This is because the exchange coupling energy due to the action of the exchange phase of magnetic atoms at the interface between the PtMn film and the NiFe film is NiFe.
It shows that it does not depend on the film thickness, and the conventional FeM
This is the same as the film thickness dependence of the NiFe film in the n film / NiFe film.

Next, the results of examining the change of Hex when changing the ferromagnetic film from NiFe to Co will be shown. Spin-
It has been already experimentally and theoretically shown that the Co resistance can be increased by using the Co film for the Pinned magnetic layer of the Valve head rather than the NiFe film, and Co is used for the Pinned magnetic layer. Since it is highly possible, it is desirable that the exchange anisotropic magnetic field with Co is also large.

The film structure of FIG. 13 is Glass / Ta (10
0A) / NiFe or Co (XA) / PtMn (20
0A) / Ta (100A), the PtMn film composition is Pt49Mn51at%, the heat treatment is held at 290 ° C. for 4 hours, and the temperature rising / falling time is 3 hours each. Even if the ferromagnetic film was changed to Co, Hex almost equal to that of the NiFe film was obtained. From this result, it can be easily inferred that similar Hex can be obtained by using a NiFeCo ternary alloy film as the ferromagnetic film.

As described above, the exchange anisotropic magnetic fields of the PtMn film and the ferromagnetic film depend on the film composition of the PtMn film, the heat treatment temperature dependence, the heat treatment holding time dependence, the PtMn film thickness dependence,
The ferromagnetic film thickness dependence was investigated in detail, and the film thickness of the ferromagnetic film in direct contact with the PtMn alloy was 50 to 300 A.
It has been shown that a large exchange anisotropic magnetic field can be obtained by subjecting the ultra-thin film to the heat treatment at 200 ° C to 350 ° C.

Next, other problems to be solved by the present invention are the thermal stability of the exchange anisotropic magnetic field and the high corrosion resistance of the antiferromagnetic PtMn film, especially NiMn and NiMnCr.
Examples are given for the comparison of corrosion resistance with the film. Finally, an example will be given regarding the difference and similarities in mechanism between the exchange anisotropic magnetic field obtained by the NiMn and NiMnCr antiferromagnetic films and the exchange anisotropic magnetic field obtained by the PtMn antiferromagnetic film. .

FIG. 14 shows the results of examining the temperature characteristics of Hex and Hc. The film composition is Glass / Ta (100A) /
NiFe (200A) / PtMn (300A) / Ta
(100 A), and the film composition of PtMn is Pt46Mn.
54at%, heat treatment at 260 ° C for 20 hours,
The temperature rising / falling time is a sample of 3 hours each. Measured with a vibrating magnetometer (VSM) vacuum degree of 5 × 10 to ⁵ Torr
While gradually heating the sample from room temperature under the following conditions, M
The -H curve was measured. Temperature rising rate during measurement is 20 ° C /
20 minutes.

Hex at room temperature is 90 Oe, which is about 1.5 times the Hex of the conventional FeMn film. The temperature at which Hex disappears (Tb: blocking temperature) is 380 ° C., and Tb = 160 of the FeMn film.
It is much higher than ° C. It is known that the temperature around the magnetoresistive effect film when the magnetic head is operating ranges from room temperature to about 120 ° C., but in this temperature range, Hex by the PtMn film shows a substantially flat value. It is clearly different from the tendency that Hex of the FeMn film decreases with temperature in the temperature range of room temperature to 120 ° C. It is very preferable that Hex and Tb are large and the value of Hex is flat in the magnetoresistive head operating temperature range because it leads to the thermal stability of the bias magnetic field, and the problem of the FeMn film is largely overcome. There is.

All the film constitutions of the above embodiments are Gl.
ass / Ta / ferromagnetic material film (NiFe or Co) / P
Although it was tMn / Ta, an example in which the order of forming the ferromagnetic film and the PtMn film is exchanged and the case where the Ta underlayer film is eliminated will be described below.

FIG. 15 shows Glass / Ta / NiFe / P.
tMn, Glass / NiFe / PtMn / Ta, Gl
ass / Ta / PtMn / NiFe / Ta, Glass
4 is a comparison of Hex in four film configurations of / PtMn / NiFe / Ta. The uppermost layer Ta is provided to prevent surface oxidation during heat treatment, and does not affect the stacking order dependency of Hex. NiFe film thickness is 20
The PtMn film has a thickness of 300 A. The film composition of PtMn is Pt49Mn51
At%, heat treatment is held at 270 ° C. for 9 hours, and temperature rising / falling time is 3 hours each.

Although the value of Hex varies somewhat depending on the stacking order, H of a good size is obtained in all stacking orders.
ex is obtained. In the conventional FeMn, the generation of the γ-FeMn phase, which is an antiferromagnetic material phase, leads to the development of the exchange anisotropic magnetic field, and a large difference appears in Hex depending on the crystal orientation and the presence or absence of the underlying Ta film for adjusting the crystal phase. It is known. That is, in the case of the FeMn film, Hex cannot be obtained unless a film for adjusting the lattice constant is laid on the underlayer, and Hex cannot be obtained by first forming the FeMn film and then forming the NiFe film. Although the device structure was restricted by this restriction, it can be seen that the Hex made of the PtMn film does not have such a restriction, is very easy to use, and can be used for a device structure that was impossible in the past. .

FIG. 16 shows experimental results when the PtMn film was replaced with a NiMn film under the same film structure, film thickness, and heat treatment conditions as in FIG. NiMn film composition is Ni
It is 49 Mn 51 at%. The characteristic of the NiMn film is that the stacking order dependence of Hex is FeMn more than that of the PtMn film.
It is similar to a film, that is, there is a large difference in Hex depending on the presence or absence of a base Ta. These facts suggest that the NiMn film and the PtMn film have slightly different mechanisms for generating the exchange anisotropic magnetic field.

Next, an explanation will be given with reference to Examples supporting the reason why the exchange anisotropy magnetic field greatly differs depending on the presence or absence of heat treatment by subjecting the interface between the PtMn film and the ferromagnetic film in direct contact with the ferromagnetic film. . Several factors are conjectured as to the reason, one of which is the formation of PtMn ordered phase (CuAu-I type) already known in existing publications such as "Magnetic Handbook", and the other is Is considered to be a change in the interface state in which the exchange anisotropic magnetic field acts, that is, the formation of an interdiffusion layer at the interface between the PtMn film and the ferromagnetic film.

20 and 21 show Auger electron spectroscopy depth profile (AES) showing the mutual diffusion state before and after heat treatment.
It is the result of examination by. as depo. The film structure is Glass / Al-O (alumina) (100A) / Ta
(80A) / NiFe (200A) / PtMn (200
A) / Ta (80A), and the film composition of PtMn is Pt.
47 Mn 53 at%, heat treatment is held at 290 ° C. for 4 hours. As depo. In the sample in the state, no clear diffusion higher than the resolution of AES was observed, but in the sample after the heat treatment in FIG. 21, the PtMn film and the N
Clear interdiffusion is observed at the interface with the iFe film. That is, Pt and Mn of PtMn, especially Mn, are diffused to the NiFe film side, and Ni and Fe of the NiFe film are diffused to the PtMn side. The diffusion distance is about 100 A or less when estimated from the film thickness of 200 A.

Considering that the exchange interaction between the magnetic atoms at the interface between the antiferromagnetic film and the ferromagnetic film is the physical origin of the exchange anisotropic magnetic field, this interdiffusion layer formed by heat treatment. Is the region itself where the exchange interaction between both magnetic atoms is working, and the exchange anisotropic magnetic field between the PtMn antiferromagnetic film and the NiFe ferromagnetic film is working via the mutual diffusion layer. In the NiFe film that is in direct contact with the PtMn film, an exchange anisotropic magnetic field is generated by performing heat treatment at 200 ° C. to 350 ° C. In particular, the higher the heat treatment temperature and the longer the heat treatment holding time, the larger the exchange anisotropic magnetic field. One reason is that the higher the heat treatment temperature and the longer the heat treatment time, the easier the formation of the interdiffusion layer.

However, mutual diffusion progresses further, and P
The tMn film and the NiFe film are completely diffused to form PtMnN.
It is certain from the mechanism of the exchange interaction that the exchange anisotropic magnetic field cannot be obtained if it becomes an iFe quaternary alloy, so it must be formed appropriately between the PtMn layer and the NiFe layer.

Regarding the expression of the exchange anisotropic magnetic field, as described above, the change in crystal structure, that is, the PtMn ordered phase (CuAu--
Since the formation of (I type) is also conceivable, the change in crystal structure before and after the heat treatment was examined by X-ray diffraction.

FIG. 22 shows an X-ray diffraction profile. The film structure is Glass / Ta (100A) / NiFe (20
0A) / PtMn (200A) / Ta (100A), the film composition of PtMn is Pt47Mn53at%, and the heat treatment is held at 290 ° C. for 4 hours. The measurement was carried out by a θ-2θ method using a Co tube.

As depo. And the difference after heat treatment is f
Similar to the PtMn {111} peak of the cc structure, there is only a slight change in the peak position of the NiMn {111} peak of the fcc structure and the change of the lattice position due to the change of the lattice constant. (C
The formation of uAu-I type) cannot be discriminated.

Next, the results of experiments relating to the improvement of corrosion resistance, which is another major object of the present invention, will be shown.

FIG. 18 shows PtMn and Ni on the glass substrate.
It is the result of examining the amount of corrosion of the film when a sample having 300 M of each of Mn and NiMnCr films was immersed in physiological saline and an emulsifier at room temperature for 24 hours. Film composition is PtM
The n film is Pt47Mn53at% and the NiMn film is Ni47.
Mn53at%, Cr addition amount is 5, 9, 13, 17at
%. The concentration of NaCl in physiological saline is 0.9%,
The emulsifier is used in various washing steps in the magnetic head manufacturing process, is a solution containing sodium tripolyphosphate, and is weakly alkaline. The amount of corrosion (%) was determined by measuring the area where the film was dissolved in the solution and the glass substrate was exposed by an optical microscope. The sample area is 4 cm ² .

Corrosion of the PtMn film did not proceed at all in the physiological saline and the emulsifier, but NiMn was 10 in both solutions.
Corrosion to expose the 0% Glass substrate progressed. NiM
Although the amount of corrosion in physiological saline was certainly reduced by adding Cr to n, the effect of the emulsifier was scarce. PtMn film is NiMn, NiMnCr
It can be seen that the corrosion resistance is much better than that of the film. FIG. 17 shows the result of examining the exchange anisotropic magnetic field in the film composition whose corrosion resistance was examined.

The film structure of FIG. 17 is Glass / Ta (10
0A) / NiFe (50 or 75A) / PtMn or NiMn or NiMnCr (200A) / Ta (1
00A) and the heat treatment is held at 270 ° C for 9 hours. Hex of the PtMn film, the NiMn film, and the NiMnCr film added with 5% and 9% of Cr showed good values, but C
Hex as the amount of r added increased to 13% and 17%
Is expected to become a practical problem. From the above results, PtMn is obtained in both the corrosion resistance and Hex of the film.
It can be seen that the film is excellent.

Finally, the results of examining the influence of the Pt amount in the PtMn film on the improvement of corrosion resistance will be shown.

FIG. 19 shows a film composition sample similar to that of FIG.
It is the result of performing the same corrosion resistance test in the solution. P
It can be easily understood that the element improving the corrosion resistance of the tMn film is Pt, and it is understood that the corrosion resistance is remarkably improved especially when the Pt amount is 44 at% or more.

In the above description, the PtMn alloy was mainly used as the diamagnetic material, but RhMn alloy, RuMn alloy, IrMn having similar attributes to these are used.
The same effect as the PtMn alloy can be expected in the alloy and the PdMn alloy.

Next, in addition to the first embodiment described above, an additional second embodiment focusing on the heat treatment temperature and the film thickness of the ferromagnetic layer will be described in detail.

FIG. 23 is a diagram showing the relationship between the exchange anisotropic magnetic field of the PtMn film formed by DC magnetron sputtering, the film thickness of the NiFe film, and the heat treatment temperature. FIG. 24 shows DC
It is a figure which shows the exchange anisotropic magnetic field of the PtMn film | membrane formed by magnetron sputtering, the heat processing temperature, the kind of ferromagnetic material layer, and the relationship of film thickness. FIG. 25 is a diagram showing the relationship between the blocking temperature of the PtMn film formed by DC magnetron sputtering, the type of ferromagnetic layer, and the film thickness. FIG. 26 shows
It is a figure which shows the experimental condition for obtaining the exchange coupling magnetic field required for the magnetoresistive head in 1st Embodiment and 2nd Embodiment.

The antiferromagnetic film for generating a necessary and sufficient exchange anisotropic magnetic field in the magnetoresistive head (MR head) includes
There is a material that needs an annealing step (heat treatment step) after forming a multilayer film such as a NiFe layer and a PtMn layer and a material that does not need it. For example, as shown in FIG. Mn-X (X = 10 to 30 at% of platinum group) is present as a magnetic film. In addition to this, as an antiferromagnetic film that does not require annealing, FeMn, Cr
-Mn-X (X = platinum group 0 to 20 at%) and NiO (nickel oxide) are present.

The annealing process for performing the high temperature treatment is performed by MR
The non-magnetic layer (for example, the Cu layer of the non-magnetic intermediate layer 8 shown in FIG. 4) in the head, particularly in the spin-valve MR head, is diffused into the upper and lower layers adjacent to each other, which deteriorates the magnetic reproducing characteristics of the MR head. There is a risk of causing it. For this reason,
When the material of the antiferromagnetic film that requires the annealing step is used, it is disadvantageous in this respect as compared with the antiferromagnetic film that does not require the annealing step because of the adverse effect of the Cu layer diffusion described above. Pt 36-54M in the first embodiment of the present invention
Even in the PtMn film of n46 to 94 atom%, the disadvantage of diffusion of the Cu layer was present. However, the strength of the generated exchange anisotropic magnetic field is not discussed here.

By the way, in the manufacturing process of the MR head, the known UV curing process (ultraviolet curing process) and hard baking process are essential manufacturing processes, and in these processes, heating to a temperature of about 250 ° C. is performed. Therefore, even if a diamagnetic material that does not require an annealing step is used, the magnetic reproducing characteristics of the MR head deteriorate in this step due to the heating temperature of 250 ° C.
On the other hand, when using a diamagnetic material that requires an annealing step, if the annealing temperature can be suppressed to 250 ° C. or less, it should be kept within the minimum damage range required in the UV curing step and the hard baking step. Can
As a result, it is possible to achieve the same damage as an antiferromagnetic film that does not require an annealing step.

In the second embodiment of the present invention, in order to form an antiferromagnetic film requiring an annealing step, DC magnetron sputtering method is adopted instead of RF conventional sputtering, and the film thickness of the ferromagnetic film is changed. Is formed thinly, whereby a stronger exchange anisotropic magnetic field is obtained, and the heat treatment temperature in the annealing step is set to 2
For example, it can be set to 50 ° C. or lower, for example, 210 ° C.

The experimental conditions for obtaining the data of the second embodiment of the present invention are shown in FIG. 26 together with the experimental conditions of the first embodiment. Here, Pt48Mn52 (a typical composition example as shown in FIGS. 5 and 6) is used as the antiferromagnetic film requiring the annealing step, and the other conditions are set to be substantially the same as those in the first embodiment. The DC magnetron sputtering method was adopted as the film forming method.

According to FIG. 23, the DC magnetron sputtering method is used, NiFe is used as the ferromagnetic film, Pt48Mn52 is used as the antiferromagnetic film, and the NiFe film thickness is 200.
The strength of the exchange anisotropic magnetic field was calculated when the thickness was changed from the thickness of angstrom to about 15 angstrom. At that time, the heat treatment temperature was set to 250 ° C, 230 ° C.
° C, 210 ° C, 190 ° C, as depo. , Are used as parameters. The NiFe film thickness actually measured in FIGS. 10 and 11 was up to 50 angstroms, but experiments were conducted up to a thickness of 15 angstroms below this.

As a result, the strength of the exchange anisotropic magnetic field of 360 Oe shown in FIG. 8 became strong up to 750 Oe. According to this experimental result, a stronger exchange anisotropic magnetic field can be obtained as the film thickness of NiFe becomes thinner. However, the thickness of 5 angstroms makes it possible to form a uniform NiFe film on the base film and exchange anisotropically. This is the limit value at which the magnetic field can be obtained, and if it is made thinner than this, there is a risk that pinholes (pores) will be generated in the film, so it cannot be made less than 5 angstroms.

Therefore, considering the strength of the exchange anisotropic magnetic field, the thickness of NiFe is generally preferably 15 to 100 Å, and the strongest exchange anisotropic magnetic field is obtained at the thickness of 15 to 30 Å. It is understood that it is possible (assuming the adoption of the DC magnetron sputtering method). Further, the higher the heat treatment temperature in the annealing step, the greater the strength of the exchange anisotropic magnetic field, but even if it is lowered to about 210 ° C, the strength of the exchange anisotropic magnetic field does not decrease so much. I also understood.

According to FIG. 24, the DC magnetron sputtering method is used and the type of ferromagnetic film and its film thickness are NiF.
e40 angstrom, Co40 angstrom,
Four types of NiFe200 angstrom and Co200 angstrom are used, and P is used as an antiferromagnetic film.
The strength of the exchange anisotropic magnetic field when t48Mn52 is adopted is actually measured.

According to this, the difference in the types of ferromagnetic films (N
(Difference between iFe and Co) (NiF as a ferromagnetic film)
(e and Co can obtain almost the same exchange anisotropic magnetic field) The difference in the film thickness affects the strength of the exchange anisotropic magnetic field. As the film is thinner, a stronger exchange anisotropic magnetic field can be obtained. In addition, the temperature is lower than 250 ° C. in the UV curing process and the hard baking process described above.
It can be seen that an exchange anisotropic magnetic field can be obtained from 0 ° C.

Further, according to FIG. 24, the strength of the exchange anisotropy magnetic field was found when the heat treatment temperature in the annealing process was variously changed, and according to this, the exchange anisotropy around 250 ° C. was obtained. The peak tendency of the magnetic field strength appears. This is shown in FIG.
The tendency of increasing the magnetic field at 250 ° C. in the first embodiment shown in FIG. 6 represents a clear difference in the tendency, and it is possible to perform the annealing temperature exceeding 250 ° C. in the UV curing process and the hard baking process described above. It indicates that there is no need.

In other words, according to the first embodiment of FIG. 6, it is possible to increase the exchange anisotropic magnetic field by increasing the heat treatment temperature in the annealing step to 350 ° C. However, on the contrary, , If the temperature is raised to 350 ° C, the above-mentioned Cu
The disadvantage is that the reproduction characteristics deteriorate due to layer diffusion.

On the other hand, another process (U
250 in V cure process and hard bake process)
Since a heating temperature of ° C is required, it is desirable that the annealing process can be appropriately performed at a temperature within 250 ° C. According to the second embodiment of FIG. 24,
Since the intensity of the exchange anisotropic magnetic field has a peak tendency at 250 ° C., there is an effect that it is not necessary to raise the heat treatment temperature to 250 ° C. or higher (assuming the adoption of the DC magnetron sputtering method).

FIG. 25 is a diagram showing the blocking temperature of the PtMn laminated film formed by DC magnetron sputtering in relation to the type of ferromagnetic film and its film thickness, even if the ferromagnetic film is NiFe or Co. However, similarly, it shows a high blocking temperature of about 380 ° C. Also, NiFe
From the comparison between Co and Co, it can be seen that NiFe can obtain a stronger exchange anisotropic magnetic field in the temperature range of 20 ° C. to 320 ° C., and NiFe is preferable in this respect.

[0081]

According to the present invention, a material having a large exchange anisotropic magnetic field, excellent temperature characteristics of the exchange anisotropic magnetic field, and excellent corrosion resistance is provided. It is possible to provide a magnetoresistive effect read head which is excellent in linear response of magnetoresistive effect by a bias magnetic field utilizing a magnetic field and can suppress Barkhausen noise.

According to the second embodiment of the present invention, the antiferromagnetic layer P formed by the DC magnetron sputtering method is used.
By using a tMn film and thinly forming the ferromagnetic layer, a stronger exchange anisotropic magnetic field can be obtained, the heat treatment temperature in the annealing step can be lowered, the blocking temperature is relatively high, and the corrosion resistance is excellent. An antiferromagnetic film can be provided.

Further, by using a PtMn film which is an antiferromagnetic layer formed by the DC magnetron sputtering method and forming a thin ferromagnetic layer, a UV curing process and a hard baking process (an essential step for manufacturing an MR head). Since the peak value of the exchange anisotropic magnetic field can be obtained at the heat treatment temperature of the annealing step in the vicinity of 250 ° C. in (1), it is equivalent to the deterioration of the reproducing characteristic when the antiferromagnetic material that does not require annealing is used. Can be suppressed.

Further, conventionally, when the ferromagnetic layer was formed thin, the blocking temperature tended to be lowered, but Pt which is an antiferromagnetic layer formed by the DC magnetron sputtering method.
By using the Mn film, a large blocking temperature can be secured even if the ferromagnetic layer is formed thin.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a bias magnetic field in an AMR head.

FIG. 2 is an explanatory diagram of a bias magnetic field in an AMR head.

FIG. 3 is an explanatory diagram of a bias magnetic field in a Spin-Valve head.

FIG. 4 is an explanatory diagram of a bias magnetic field in a Spin-Valve head.

FIG. 5 is a diagram showing a relationship between a film composition of a PtMn film and an exchange anisotropic magnetic field.

FIG. 6 is a diagram showing a relationship between a film composition of a PtMn film, a heat treatment temperature, and an exchange anisotropic magnetic field.

FIG. 7 is a diagram showing a relationship between a heat treatment temperature and a holding time of a PtMn film and an exchange anisotropic magnetic field.

FIG. 8 is a diagram showing a relationship between a heat treatment temperature and a holding time of a PtMn film and a coercive force.

FIG. 9 is a diagram showing the relationship between the film thickness of the PtMn film, the heat treatment temperature, and the exchange anisotropic magnetic field.

FIG. 10 is a diagram showing a relationship between a film thickness of NiFe film, a heat treatment temperature, a holding time and an exchange anisotropic magnetic field.

FIG. 11 is a diagram showing the relationship between the film thickness of NiFe film, the heat treatment temperature, the holding time and the exchange anisotropic magnetic field.

FIG. 12 is a diagram showing the relationship between the film thickness of the PtMn film, the film thickness of the NiFe film, the heat treatment temperature, the holding time and the exchange anisotropic magnetic field.

FIG. 13 is a diagram showing a comparison of exchange anisotropic magnetic fields of a NiFe film and a Co film.

FIG. 14 is a diagram showing a relationship between an exchange anisotropic magnetic field and a measurement temperature.

FIG. 15 is a diagram showing a comparison of exchange anisotropic magnetic fields of the PtMn film with and without the underlying Ta film when the stacking order is changed.

FIG. 16 is a diagram showing a comparison of exchange anisotropic magnetic fields of the NiMn film when the stacking order is changed and when the underlying Ta film is used.

FIG. 17 is a diagram showing a comparison of exchange anisotropic magnetic fields by PtMn, NiMn, and NiMnCr films.

FIG. 18 is a diagram showing a comparison of corrosion resistance of PtMn, NiMn, and NiMnCr films.

FIG. 19 is a diagram showing the relationship between the film composition of a PtMn film and corrosion resistance.

FIG. 20: as depo. By Auger electron spectroscopy depth profile It is a figure which shows the interface diffusion state of a state.

FIG. 21 is a diagram showing an interface diffusion state after heat treatment by Auger electron spectroscopy depth profile.

FIG. 22 is a diagram showing an analysis result of a film structure by an X-ray diffraction profile.

FIG. 23: PtM deposited by DC magnetron sputtering
It is a figure which shows the exchange anisotropic magnetic field of n film | membrane, the film thickness of NiFe film | membrane, and the relationship of heat processing temperature.

FIG. 24: PtM deposited by DC magnetron sputtering
It is a figure which shows the exchange anisotropic magnetic field of n film | membrane, the heat processing temperature, the kind of ferromagnetic material layer, and the relationship of film thickness.

FIG. 25: PtM deposited by DC magnetron sputtering
It is a figure which shows the blocking temperature of n film | membrane, the kind of ferromagnetic material layer, and the relationship of film thickness.

FIG. 26 is a diagram showing experimental conditions for obtaining an exchange anisotropic magnetic field necessary for the magnetoresistive head in the first embodiment and the second embodiment.

[Explanation of symbols]

 1 Soft Magnetic Material Layer 2 Electrical Insulation Layer 3 Ferromagnetic Layer 4 Diamagnetic Layer 5 Conductive Layer 6 Magnet 7 Free Magnetic Layer 8 Nonmagnetic Intermediate Layer 9 Pinned Magnetic Layer 10 Antiferromagnetic Layer 11 Magnet 13 Antiferromagnetic Layer

Claims (17)

[Claims] 1. A magnetoresistive head comprising a ferromagnetic layer exhibiting a magnetoresistive effect and an antiferromagnetic layer in direct contact with the ferromagnetic layer, wherein the antiferromagnetic layer is made of a PtMn alloy. A magnetoresistive head, which has been heat-treated and produces an exchange anisotropic magnetic field at the interface with the ferromagnetic layer that is in direct contact with the antiferromagnetic layer. 2. The film composition of the PtMn alloy according to claim 1, wherein Pt5 to 54Mn46 to 9 are used.
5 atomic% and the heat treatment temperature is 200 ° C to 35 ° C.
A magnetoresistive head having a range of 0 ° C. 3. The film composition of the PtMn alloy according to claim 1, wherein the PtMn alloy has a film composition of Pt5-20Mn80-9.
5 atomic% and the heat treatment temperature is 200 ° C to 35 ° C.
A magnetoresistive head having a range of 0 ° C. 4. The film composition of claim 1, wherein the PtMn alloy has a film composition of Pt36 to 54Mn46.
64 at%, the heat treatment temperature is 200 ° C. to 3
A magnetoresistive head having a temperature range of 50 ° C. 5. A magnetoresistive head comprising a ferromagnetic layer exhibiting a magnetoresistive effect and an antiferromagnetic layer in direct contact with the ferromagnetic layer, wherein the antiferromagnetic layer is made of a PtMn alloy. The heat treatment is performed, and the thickness of the interdiffusion layer formed at the interface between the antiferromagnetic material layer and the antiferromagnetic material layer is 20.
A magnetoresistive head having a thickness of 100 A (angstrom). 6. The film composition of the ferromagnetic layer according to claim 1, wherein a film composition of the ferromagnetic layer is NiFe alloy or NiFeC.
A magnetoresistive head, which is one of an o alloy and Co. 7. The film according to claim 1, wherein the antiferromagnetic material layer has a thickness of 100 to 500 A (angstrom), and the ferromagnetic material layer has a thickness of 5 nm. ~ 300
A magnetoresistive head of A (Angstrom). 8. The RhM according to claim 1, in place of the PtMn alloy that is the antiferromagnetic material layer.
A magnetoresistive head, comprising any one of an n alloy, a RuMn alloy, an IrMn alloy, and a PdMn alloy. 9. A ferromagnetic layer exhibiting a magnetoresistive effect and Pt.
200 to 3 by directly contacting with the antiferromagnetic layer of Mn alloy
Manufacture of a magnetoresistive head in which a heat treatment is performed at a temperature of 50 ° C., and the temperature is maintained for 4 to 20 hours to form an interdiffusion layer at the interface between the ferromagnetic layer and the antiferromagnetic layer in direct contact Method. 10. The method according to any one of claims 1 to 6.
In one claim, the thickness of the antiferromagnetic layer is 10
A magnetoresistive head having a thickness of 0 to 500 A (angstrom) and a thickness of the ferromagnetic layer of 15 to 300 A (angstrom). 11. The method according to any one of claims 1 to 6.
In one claim, the thickness of the antiferromagnetic layer is 10
A magnetoresistive head having a thickness of 0 to 500 A (angstrom) and a thickness of the ferromagnetic layer of 50 to 300 A (angstrom). 12. The method according to any one of claims 1 to 6.
In one claim, the thickness of the antiferromagnetic layer is 10
A magnetoresistive head having a thickness of 0 to 500 A (angstrom) and a thickness of the ferromagnetic layer of 15 to 100 A (angstrom). 13. The method according to any one of claims 1 to 6.
In one claim, the thickness of the antiferromagnetic layer is 10
A magnetoresistive head having a thickness of 0 to 500 A (angstrom) and a thickness of the ferromagnetic layer of 15 to 30 A (angstrom). 14. The method of manufacturing a magnetoresistive head according to claim 9, wherein the ferromagnetic material layer and the antiferromagnetic material layer are formed by a DC magnetron sputtering method. 15. A ferromagnetic layer exhibiting a magnetoresistive effect and P
Direct contact is made with the antiferromagnetic layer of tMn alloy, and the film is formed using the DC magnetron sputtering method at 210 ° C to 25 ° C.
A method of manufacturing a magnetoresistive head, in which heat treatment is performed at an annealing temperature of 0 ° C. to form an interdiffusion layer at the interface between the ferromagnetic layer and the antiferromagnetic layer that are in direct contact with each other. 16. A ferromagnetic layer exhibiting a magnetoresistive effect and P
The antiferromagnetic material layer of tMn alloy is brought into direct contact, and a film is formed by using a DC magnetron sputtering method and heat-treated at an annealing temperature near 250 ° C. so that the exchange anisotropic magnetic field has a substantially peak value. A method of manufacturing a magnetoresistive head, comprising forming an interdiffusion layer at an interface between a ferromagnetic layer and an antiferromagnetic layer that are in direct contact with each other. 17. A magnetoresistive head comprising a ferromagnetic layer exhibiting a magnetoresistive effect and an antiferromagnetic layer in direct contact with the ferromagnetic layer, wherein the antiferromagnetic layer comprises a PtMn alloy. The film composition thereof is Pt 5 to 20 Mn 80 to 95 atom%, and an exchange anisotropic magnetic field immediately after film formation is generated at the interface with the ferromagnetic layer that is in direct contact with the antiferromagnetic layer. A magnetoresistive head.