JPH09282612A - Magnetoresistance effect head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably control the output with a rather weak vertical bias magnetic field and to improve reproducibility of signals having a large output amplitude in a magnetoresistance effect head by forming an exchange spring magnet film for a permanent magnet film. SOLUTION: An insulating film 12 is formed on a lower shield film 2, on which an MR film 11 and nonmagnetic film 10 are formed, and a base film 4, exchange spring magnet film 7 and SAL film 9 are formed to surround the films 11, 10. Further, an electrode 3 is formed on both sides of a track width regulating film 8, and an insulating film 12 and an upper shield film 1 are formed thereon. The magnet film 7 consists of a hard magnetic phase 5 and a soft magnetic phase 6. By changing the thickness ratio of layer thickness between the hard magnetic phase 5 and the soft magnetic phase 6 of the magnet film 7, the product of the residual magnetic flux density and the film thickness can be controlled to 5 to 40Tnm. By controlling the film thickness of the base film, Hc can be controlled to >1200Oe. Thereby fluctuation in the magnetic field caused by fluctuation the magnetization state of the MR or SAL film by a transverse bias magnetic field can be enough suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head for reading a magnetic information signal from a magnetic medium.

[0002]

2. Description of the Related Art Magnetoresistive head (MR head)
Is conventionally known as a magnetic head capable of reading data recorded on a magnetic recording medium with high recording density. This head is widely used as a read-only head of a recording / playback separation type head that uses dedicated heads for recording and reproduction. This head detects an information signal from a medium by utilizing the fact that the resistance of a magnetoresistive effect element (MR element) made of a material exhibiting a magnetoresistive effect changes as a function of the strength and direction of an external magnetic field. Is.

Various MR heads have been developed and have been used conventionally to meet the requirements of recording / reproducing devices. However, the recording / reproducing apparatus is required to have a higher recording density, the track width becomes narrower, and the linear recording density in the direction perpendicular to the track also becomes higher. With the conventional MR head manufacturing technique, it is becoming difficult to obtain an MR head adapted to a narrow track width and a high linear recording density.

In the conventional MR head, two bias magnetic fields which are orthogonal to each other must be applied in order for the MR element to operate optimally. One is a lateral bias magnetic field for biasing the MR element so that the response to the magnetic field becomes linear. This bias magnetic field is perpendicular to the surface of the magnetic medium and parallel to the element height direction of the MR element. The other bias magnetic field is a longitudinal bias magnetic field which is parallel to the surface of the magnetic medium and extends parallel to the longitudinal direction which is the easy axis direction of the MR element. The purpose of this longitudinal bias magnetic field is to suppress noise (Barkhausen noise) caused by the multi-domain structure in the MR element.

Japanese Unexamined Patent Publication (Kokai) No. 52-062417 discloses an MR head using a method (SAL bias method) of applying a lateral bias magnetic field by utilizing the saturation magnetization of a soft magnetic film (SAL film). . On the other hand, Japanese Patent Laid-Open No. 57-198528 discloses an MR in which an MR element is separated from a bias film by an insulating film.
A head is disclosed, and the track width is defined by the inner spacing of the signal detection electrodes of the head. JP 64
-35717 discloses a track width regulation method in which an insulating film is inserted. Further, Japanese Patent Laid-Open No. 7-210828 discloses a method of increasing coercive force by forming a permanent magnet film into a multilayer structure.

[0006]

In the bias method disclosed in these prior arts, a permanent magnet film such as a CoPt film is generally used as a longitudinal bias magnetic field generating film. However, the coercive force of the CoPt film is as small as about 800 Oe, and the magnetization state changes due to the magnetic field generated during recording / reproducing of the head, so the longitudinal bias magnetic field fluctuates, and the amplitude and waveform of the output signal change greatly. I will end up.

According to the simulations by the authors, although it depends on the conditions such as the residual magnetic flux density of the medium, the film thickness, the flying height, the gap length, and the recording current flowing in the thin film induction type recording head, each of them is 300 in the vicinity of the medium facing surface. ~ 400 O
A medium magnetic field and recording magnetic field of about e leak to the permanent magnet film. MR or S by medium magnetic field or lateral bias magnetic field
Regarding the magnetic field generated by the change in the magnetization state of the AL film, a magnetic field of about 500 to 600 Oe leaks to the permanent magnet film near the track width boundary. Since the magnetization state of the permanent magnet film near the track width boundary has the greatest effect on the generation of longitudinal bias,
As a coercive force of the permanent magnet film, a value of about 1000 Oe, preferably about 1200 Oe is desired.

When the coercive force of the permanent magnet film is insufficient with respect to the above-mentioned magnetic field generated during recording / reproducing of the head,
The longitudinal bias field must be set strong, which reduces the output amplitude. The decrease in the reproduction output due to the increase in the longitudinal bias magnetic field became more remarkable as the signal recording wavelength (linear recording density) became shorter. Also, as the track width becomes narrower, the reproduction output from the MR head decreases more and more, and signal detection tends to be difficult. This tendency becomes more remarkable as the vertical bias magnetic field is stronger.

Further, as the linear recording density increases, the gap length (distance between the upper and lower shield films) also decreases. From the viewpoint of electrical insulation between the MR film and the SAL film and the shield film, each insulating film needs to have a thickness of about 0.1 μm, and the MR film and the permanent magnet film must be made thinner as the gap length becomes narrower. However, in the CoPt film or the like used in the conventional permanent magnet film, the coercive force reaches its maximum value at a film thickness of about 50 nm, and the coercive force sharply decreases below 50 nm. Even in the conventional permanent magnet film, the coercive force can be improved to some extent by changing the composition. However, when the coercive force is increased depending on the composition ratio, the residual magnetic flux density Br decreases.
The longitudinal bias magnetic field is the residual magnetic flux density Br of the magnet film and the film thickness t.
Since it is almost proportional to the product of and, increasing the coercive force makes it difficult to apply a longitudinal bias magnetic field sufficient to prevent the MR film from becoming multi-domain.

On the other hand, if the element height of the MR element is too low, the demagnetizing field in the element height direction becomes strong, so that an appropriate lateral bias cannot be obtained and the output decreases. The demagnetizing field in the element height direction rapidly increases near the element height of 1.0 μm, so 1.0
The output is highest around μm. When the track width is narrowed in order to achieve higher density with respect to this optimum element height, the aspect ratio (= track width / element height) of the MR film and the SAL film decreases, and the magnetization state becomes It becomes stable and it becomes difficult to maintain the single domain state. Therefore, as the track width becomes narrower, the required strength of the longitudinal bias magnetic field is applied, and
It is important to maintain the single magnetic domain state of the R element.

Therefore, according to the present invention, in a narrow track MR element in which a longitudinal bias magnetic field and a lateral bias magnetic field exist, an MR head capable of detecting an output signal having a large amplitude with good reproducibility and hardly causing Barkhausen noise. It is provided.

[0012]

According to the present invention, by using an exchange spring magnet film having a coercive force of 1000 Oe or more as the permanent magnet film, a signal having a reproduction output amplitude larger than that of a conventional head is detected with good reproducibility, and a bulk An MR head in which Hausen noise is sufficiently suppressed is provided.

As such a permanent magnet film, a soft magnetic phase (soft magnetic phase having a magnitude of magnetization of 0.9 T or more) and a hard magnetic phase (5 to 20 at% R (R is a rare earth element containing Y) At least one), 0 to 25 at% of X (B, C, N, etc.), the balance transition metal (TM is Fe or Co or Ni or an alloy thereof) and a hard magnetic phase containing unavoidable impurities) 1
By using a rare earth magnet type exchange spring magnet film in which two or more layers are laminated, a film having a coercive force of 1000 Oe or more and a residual magnetic flux density of 0.2 to 1.5 T can be obtained.

3 nm or more and 50 nm or more in at least one of the multilayer films in which the soft magnetic phase and the hard magnetic phase of the exchange spring magnet film are laminated.
Protective layers (Cr, Ti, W, Mo, Cu, Ta,
FeMn, NiMn, NiO, FeO, CoO, Co-Pt, Fe
-By forming a layer consisting of one or more of Pt), the in-plane coercive force is 1000 Oe in a relatively wide composition range.
The above film is obtained. This is because the protective layer suppresses the oxidation of the soft magnetic phase or the hard magnetic phase and the reaction with the substrate.

[0015]

According to the present invention, in the MR head in which the longitudinal bias magnetic field and the lateral bias magnetic field exist, it is possible to prevent the MR film and the SAL film from becoming multi-domain and to suppress the generation of head noise due to the multi-domain. Within the range, the magnetic field leaking from the permanent magnet film can be weakened, and a signal with a large amplitude can be detected with good reproducibility.

In the present invention, as the permanent magnet film, a soft magnetic phase (a soft magnetic phase having a magnitude of magnetization of 0.9 T or more) and a hard magnetic phase (5 to 20 at% R (R is a rare earth element containing Y) are used. At least one), 0 to 25 at% X (B, C, N, etc.), the balance transition metal (Fe or Co or Ni or alloys thereof) and a hard magnetic phase containing inevitable impurities) as a single layer Alternatively, by using a rare earth magnet type exchange spring magnet film laminated with two or more layers, the magnetic field leaking from this permanent magnet film is weakened to the extent that noise generation is suppressed, and a magnetoresistive effect that can obtain a signal with a large output amplitude with good reproducibility. A mold head is provided.

The exchange spring magnet film is obtained by combining a soft magnetic phase having a large magnetization and a hard magnetic phase having a large coercive force as shown in FIG. 1 and magnetically combining them to obtain a high energy product. Is. Generally, in a permanent magnet material, if there is a soft magnetic phase that exchange-couples with a hard magnetic phase,
The magnetization reversal begins first in the soft magnetic phase under a reverse magnetic field, which is the main cause of the decrease in coercive force. However, if the size of the soft magnetic phase is suppressed to the domain wall width or less, the non-uniform magnetization reversal under the reverse magnetic field is suppressed. As a result, the coercive force is mainly controlled by the magnetic anisotropy of the hard magnetic phase, and the decrease is suppressed. On the other hand, in order to obtain a higher magnetic flux density from the soft magnetic phase, it is necessary to increase the volume ratio of the soft magnetic phase. For this purpose, the size of one hard magnetic phase should be made as small as possible. That is, the design guideline is to increase the film thickness of the hard magnetic phase in order to obtain a higher coercive force and to increase the film thickness of the soft magnetic phase in order to obtain a higher magnetic flux density. The size of the hard magnetic phase may be equal to or less than the domain wall width, but if it is too narrow, it becomes difficult to maintain the coercive force. When the hard magnetic phase is Nd ₂ Fe ₁₄ B, its size is 5 nm to 30
It will be about nm. Such an exchange spring magnet film has a composite structure of a hard magnetic phase and a soft magnetic phase having an average crystal grain size of several to several tens of nm as shown in FIG. Can also be obtained by For the reasons mentioned above,
The average crystal grain size of the hard magnetic phase is preferably 5 nm or more and 30 nm or less. As with the multilayer structure, the design guideline is to increase the composition ratio of the hard magnetic phase to obtain a higher coercive force and increase the composition ratio of the soft magnetic phase to obtain a higher magnetic flux density.

In addition to the size control of each phase described above, as a condition for obtaining a high coercive force as an exchange spring magnet film, the coercive force of the hard magnetic phase is sufficiently drawn out and the mutual exchange of the hard magnetic phase and the soft magnetic phase is performed. Two points are necessary to make the action sufficiently strong. However, the hard magnetic phase composed of a rare earth magnet has poor corrosion resistance, and if the oxidation is not sufficiently suppressed, R2TM14X
Since (TM is a transition metal) is hard to be generated and the coercive force of the hard magnetic phase is lowered, the coercive force of the exchange spring magnet film is likely to be deteriorated. Therefore, as a protective film for suppressing oxidation due to thinning, at least 3 nm or more and 50 n or more are formed on at least one of the multilayer films of the soft magnetic phase and the hard magnetic phase of the exchange spring magnet film.
Protective layer (Cr, Ti, W, Mo, Cu, Ta,
FeMn, NiMn, NiO, FeO, CoO, Co-Pt, Fe
-A layer consisting of one or more of Pt) was formed. With such a protective film, a film having an in-plane coercive force of 1000 Oe or more and a residual magnetic flux density of 0.2 to 1.5 T can be obtained in a relatively wide composition range. This is because the protective layer suppresses the oxidation of the soft magnetic phase or the hard magnetic phase and the reaction with the substrate, and as a result, the exchange coupling between the hard magnetic phase and the soft magnetic phase becomes strong, and a multilayer film having excellent magnetic properties can be obtained. Because you can.

To bring out the coercive force of the hard magnetic phase sufficiently, R2
A heat treatment is required to obtain a polycrystal of TM14B.
A heat treatment temperature of 500 ° C or higher is suitable from the viewpoint of maximizing the coercive force of the hard magnetic phase, but 300 ° C or lower is preferable from the heat resistance of the MR head. By suppressing the oxidation in the protective layer as described above, 1000 even at a heat treatment temperature of 250 ° C.
A coercive force of Oe or more is obtained.

In FIG. 3, the amplitude of the output signal of the conventional head and the Barkhausen noise occurrence probability are indicated by a circle. A CoPt film and a CoCrPt-based film were used as the permanent magnet film. Film thickness t
Alternatively, each Br was changed depending on the composition ratio of the CoCrPt-based film.
With respect to the sample head of the set, the recording / reproducing process was repeated 20 times and the reproduced waveform was observed with an oscilloscope. The sense current was 13 mA.

When any of the peak value fluctuation, the waveform jump, and the baseline shift, which are obvious by visual observation, appeared during the above repeated measurement, it was considered that Barkhausen noise had occurred in the sample head.

Since various noises are generated in the reproduced waveform in addition to the signal, it is difficult to distinguish between the signal and the noise when the output amplitude is low. The output amplitude had the maximum value when the product of Br and film thickness t of the permanent magnet film was around 12.5 Tnm. When Br · t = 10 Tnm or less, the longitudinal bias magnetic field is insufficient, so that the MR film cannot maintain a single domain state, and Barkhausen noise is rapidly increasing.
On the other hand, when Br · t ≧ 12.5 Tnm, the reproducing amplitude decreases as Br · t becomes stronger, and the reproducing amplitude decreases remarkably at 30 Tnm or more. This is because the longitudinal bias magnetic field increases almost in proportion to Br · t, and thus the change in the magnetization state of the MR film with respect to the medium signal decreases as Br · t increases. A region where the output amplitude is relatively large and Barkhausen noise can be substantially suppressed is a range of Br · t desirable as a permanent magnet film of an MR head. It is assumed that such a range changes depending on the track width and the like, but it is 12.5 to 25 Tnm under the conditions of FIG.

Further, the average value of the output amplitude for each Br · t is indicated by a circle, and the measurement variation is indicated by an error bar. The output amplitude showed a considerable variation regardless of Br · t. This is probably because the magnetization state of the MR or SAL film varied. The magnetization states of the MR and SAL films are strongly affected by the longitudinal bias magnetic field, and it is considered that the cause of the characteristic variation of the conventional head is that the longitudinal bias magnetic field from the permanent magnet film fluctuates. This is because the coercive force Hc of the permanent magnet film of the conventional head is as small as about 800 Oe, and the magnetic field leaks to the permanent magnet film during the recording / reproducing process (the magnetic field from the medium, the recording magnetic field from the recording section, the medium magnetic field or the lateral bias magnetic field). It is considered that the change in the magnetization state of the permanent magnet film due to the magnetic field generated by the change in the magnetization state of the MR or SAL film due to (4) could not be suppressed.

FIG. 4 shows a head for high recording density as shown in FIG.
This is an example in which the track width and the gap length are narrower than the above.
In the conventional head indicated by a circle, the output is reduced and the Barkhausen noise appearance probability is increased as compared with FIG. This is because the permanent magnet film is thinned to 30 nm as the gap length is narrowed, so that the conventional magnet film can only obtain a coercive force of about 300 Oe, which is sufficient to prevent the MR and SAL films from becoming multi-domain. Because a strong longitudinal bias magnetic field was not obtained,
Inferred.

FIG. 5 shows the film thickness dependence of the coercive force of the exchange spring magnet film used in the present invention. In the conventional CoPt magnet film, the coercive force is as small as about 800 Oe, and the coercive force sharply decreases at a film thickness of 50 nm or less. On the other hand, the exchange spring magnet film used in the present invention has a coercive force of about 1500 Oe, which is sufficiently higher than the desired coercive force of 1000 Oe predicted by simulation. Further, the exchange spring magnet film used in the present invention does not decrease the coercive force even when the film thickness becomes thin, and is promising as a material for a head compatible with high linear recording density.

FIG. 6 shows an example of controlling the coercive force of the exchange spring magnet film used in the present invention by changing the film thickness ratio of the hard magnetic phase and the soft magnetic phase. The thickness of the magnet film was 40 nm. B
Regarding r · t, both the conventional magnet film and the exchange spring magnet film used in the present invention have a desirable Br · t range 1 under the conditions of FIG.
It satisfies 2.5 to 25 Tnm. Regarding the coercive force, the exchange spring magnet film sufficiently satisfied the coercive force of 1000 Oe predicted by the simulation, but the conventional magnet film could only obtain the coercive force of 800 Oe.

A method of increasing the coercive force by forming the permanent magnet film into a multilayer structure is disclosed in Japanese Patent Application Laid-Open No. 7-210828. However, in the above publication, by laminating the hard magnetic phase and the protective layer, the in-plane orientation and corrosion resistance of the permanent magnet film are improved and the coercive force is increased.
Unlike the present invention, the coercive force is not increased by utilizing the exchange interaction between the hard magnetic phase and the soft magnetic phase.

[0028]

EXAMPLES The present invention will be described in detail below with reference to examples. (Embodiment 1) FIG. 1 and FIG. 7 are structural views of a recording / reproducing separation type head and an enlarged sectional view of an MR element part of a SAL bias MR head in which a permanent magnet film and electrodes are formed as longitudinal bias films in end regions. And indicates.

In this embodiment, the MR film (Ni-Fe) 11 and the non-magnetic film T are formed on the lower shield film 2 with the insulating film 12 interposed therebetween.
(A) (10) is sandwiched between the underlying (Ti) film 4, the exchange spring magnet film (hard magnetic phase (Nd ₁₄ Fe ₇₇ B ₉ ) 5, soft magnetic phase (NiFe) 6) 7, SAL film (Ni- Fe-Cr) 9 was laminated, and the electrode (Mo) 3 was further formed (with the insulating track width regulating layer 8 sandwiched therebetween. Further, the upper shield film 1 was formed via the insulating film 12.

The product of the residual magnetic flux density and the film thickness was controlled to 5 to 40 Tnm by changing the layer thickness ratio of the hard magnetic phase and the soft magnetic phase of the exchange spring magnet film. By controlling the underlayer film thickness, Hc was set to 1200 Oe or more. At this time, the Al ₂ O ₃ film of the track width regulating layer was processed by wet etching to have a width of 2.2 μm. The element height of the MR film is
1.6μm, the gap between the upper and lower shield films (gap length) is 0.2
8 μm, the thickness of the magnet film is 50 nm.

Recording was performed on the medium by using the inductive head 13 actually formed on the MR element, and the reproducing characteristic of the MR element was examined. At this time, the track width of the inductive head is 3μ.
An m-width head was used. As a study of Barkhausen noise, the recording and reproducing process was repeated 20 times and the reproduced waveform was observed with an oscilloscope. Then, during the repeated measurement, if any of the fluctuation of the peak value, the jump of the waveform, and the baseline shift, which are obvious by visual observation, appeared, it was determined that Barkhausen noise appeared in the sample head. The sense current was 13 mA. 20 sets of sample heads were prepared for the exchange spring magnet film of each layer thickness ratio, and a recording current of 0.3 AT was applied to the thin film induction type recording head.
Was applied and the above repeated measurement was performed. The reproduction output shows the average value and the variation for each layer thickness ratio.

As a result, as shown in FIG. 3, the MR reproduction output increased as the product of the residual magnetic flux density Br and the film thickness t of the permanent magnet film decreased. The reproduction output at each Br · t is the conventional CoPt.
It shows almost the same tendency as when using the film or the CoCrPt system, and it seems that the control of the longitudinal bias magnetic field is effective for increasing the reproduction output. Conventional CoPt film or CoCr
When the Pt system was used, there were large variations, but
When using the exchange spring magnet film, the variation was considerably small, and the output variation for the same head was less than 2%. The lower limit of Br · t at which the output decreases and the Barkhausen noise appearance probability increases sharply is 7.5 Tnm, which is lower than that of the conventional head, and it is possible to obtain a large output signal by designing Br · t smaller than that of the conventional head. Be done.

As described above, in this embodiment, the longitudinal bias magnetic field is designed to be weaker than that of the conventional head, and a signal having a large output amplitude can be obtained with good reproducibility. This is because the exchange spring magnet film used for the permanent magnet film has a coercive force of 1200 Oe or more, which is higher than 800 Oe of the conventional head, and the magnetic field leaking to the permanent magnet film during the recording / reproducing process (the magnetic field from the medium, the recording magnetic field from the recording unit). It is considered that the change of the magnetization state of the permanent magnet film due to the magnetic field generated by the change of the magnetization state of the MR or SAL film due to the medium magnetic field or the lateral bias magnetic field was sufficiently suppressed.

(Example 2) MR having the same structure as that of Example 1
A head was manufactured and the reproduction characteristics and Barkhausen noise of the MR head were evaluated. However, a head with a track width of 1.5 μm, an MR film height of 1 μm, a gap length of 0.2 μm, and a magnet film thickness of 300 A was prototyped as a head for higher density. Further, in order to evaluate the Barkhausen noise suppression condition when the leakage magnetic field at the time of recording is relatively large, the excitation of the induction type head was set to 0.4 AT. As a permanent magnet film, an exchange spring magnet film (hard magnetic phase Nd ₁₂ Dy ₂ Fe ₆₀ Co
₁₈ B ₈ , soft magnetic phase NiFe) was used, and the ratio of the residual magnetic flux density to the film thickness was controlled to 5 to 40 T · nm by changing the layer thickness ratio. Hc is set to 150 by controlling the underlayer film thickness.
It was set to 0 Oe or more. 20 sets of sample heads were prepared for each layer thickness.

As a result, as shown in FIG.
As shown in FIG. 3, the output decreases and the Barkhausen noise appearance probability increases as compared with FIG. This is because the conventional magnet film can only obtain a coercive force of about 300 Oe at a film thickness of 30 nm.
It is presumed that the longitudinal bias magnetic field sufficient to prevent the multi-domain structure of the film and the SAL film was not obtained. On the other hand, when the exchange spring magnet film is used, Br · t ≧ 10
At Tnm, Barkhausen noise can be almost suppressed, and an output amplitude comparable to the comparatively low density in FIG. 3 can be obtained with good reproducibility. Therefore, the exchange spring magnet film is more advantageous than the conventional magnet film in achieving high linear recording density and narrow track density.

[0036]

According to the present invention, the SAL bias method M
By applying an optimized longitudinal bias in the R head, the magnetization state of the magnetoresistive film was stably controlled by a comparatively weak longitudinal bias magnetic field, and a signal with a large output amplitude was obtained with good reproducibility.

[Brief description of drawings]

FIG. 1 is a sectional view of an MR head that is an embodiment according to the present invention.

FIG. 2 is an MR head according to another embodiment of the present invention.

FIG. 3 shows reproduction output amplitude and Barkhausen noise appearance probability characteristics according to the present invention.

FIG. 4 is characteristics of another embodiment of the present invention.

FIG. 5 shows the film thickness dependence of the coercive force of the permanent magnet film and the exchange spring magnet film.

FIG. 6 shows the relationship between the product of the permanent magnet film and the residual magnetic flux density Br and the coercive force.

FIG. 7 is a structural diagram of a conventional recording / reproducing separation type head.

[Explanation of symbols]

1 lower magnetic pole and upper shield film, 2 lower shield film,
3 electrodes, 4 protective layer 5 hard magnetic phase, 6 soft magnetic phase, 7 exchange spring magnet film, 8 insulating track width regulation layer, 9 SAL film, 10
Non-magnetic film, 11 MR film, 12 insulating film, 13 thin film inductive recording head, 14 magnetoresistive head 1
5 top pole, 16 coils, 17 element height of MR element, 18 substrate.

Claims (6)

[Claims] 1. A laminated body in which an MR film (magnetoresistive film), a nonmagnetic film, a SAL film (soft magnetic film) and an insulating film are sequentially formed on a substrate, and the permanent magnet is adjacent to the laminated body. A magnetoresistive head (MR head) to which a longitudinal bias magnetic field is applied by a film, wherein the permanent magnet film is an exchange spring magnet film. 2. The magnetoresistive head according to claim 1, wherein the exchange spring magnet film has a coercive force of 1000 Oe.
The above is a magnetoresistive effect magnetic head. 3. The magnetoresistive head according to claim 1, wherein the exchange spring magnet film is an S layer (a soft magnetic phase having a magnetization magnitude of 0.9 T or more) and an H layer. (5 to 20 at% R (R is at least one of rare earth elements including Y), 0 to 25 at% X (B, C or N), balance transition metal (Fe or Co or Ni or alloys thereof)) And a hard magnetic layer containing inevitable impurities)
A magnetoresistive effect magnetic head comprising: a rare earth magnet type exchange spring magnet film, which is composed of one layer or two or more layers. 4. The magnetoresistive head according to claim 1, wherein a protective layer (Cr, T) having a film thickness of 3 nm or more and 50 nm or less is provided on at least one of the surfaces of the permanent magnet film which are in contact with the insulation.
i, W, Mo, Cu, Ta, FeMn, NiMn, NiO, Fe
A magnetoresistive effect magnetic head, which is a rare earth magnet type exchange spring magnet film on which one or more layers of O, CoO, Co-Pt, and Fe-Pt are formed. 5. The magnetoresistive head according to claim 1, wherein the exchange spring magnet film has a soft magnetic phase having an average crystal grain size of several to several tens nm (magnetization magnitude of 0.9 T or more). Certain soft magnetic phase) and hard magnetic phase (5 to 20 at% R (R
Is at least one of rare earth elements including Y), 0 to 25 at%
X (B, C or N), the balance transition metal (Fe, Co, N)
A magnetoresistive effect magnetic head comprising a rare earth magnet type exchange spring magnet film having a composite structure of i or alloys thereof and a hard magnetic phase containing inevitable impurities). 6. The magnetoresistive head according to claim 5, wherein an average crystal grain size of the hard magnetic phase contained in the exchange spring magnet film is 5 nm or more and 30 nm or less. Magnetic head.