JPH10302203A - Vertical magnetic recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high speed high density recording using a medium having an easy axis of magnetization in the direction vertical to the surface of a film and reproducing the recording information of a vertical magnetization film through a reproducing means having a structure where two spin valve elements having a specified difference in the magnetizing direction of a fixed layer are laminated. SOLUTION: A difference of 180 deg. is set in the magnetizing direction between magnetization fixed layers 44, 49 constituting a part of first and second spin valves 34, 33, respectively. The spin valves 34, 33 are laminated through a nonmagnetic film 36. In order to set a soft magnetic layer constituting a giant magnetoresistive element as a single magnetic domain and to arrange the magnetizing direction unidirectionally, the magnet pattern of high coercive force is magnetized in parallel with a line α. According to the structure, a reproduction signal having Gaussian waveform is obtained even when a vertically magnetized film is employed as a recording medium and a similar signal processing can be ensured even when an in-plane magnetization film is employed as a recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus used for an electronic computer and an information processing apparatus, and more particularly to a perpendicular magnetic recording apparatus suitable for realizing high-density recording.

[0002]

2. Description of the Related Art A semiconductor memory and a magnetic memory are mainly used as storage (recording) devices of information equipment. Semiconductor memory is used for the internal storage device from the viewpoint of access time,
A magnetic memory is used for an external recording device from the viewpoint of large capacity and non-volatility. Today, the mainstream of magnetic memory is on magnetic disks and magnetic tapes. In the recording media used for these, a magnetic thin film is formed on an Al substrate or a resin tape. In order to write magnetic information on these recording media, a functional unit having an electromagnetic conversion function is used.
Further, in order to reproduce magnetic information, a functional unit utilizing a magnetoresistance phenomenon, a giant magnetoresistance phenomenon, or an electromagnetic induction phenomenon is used. These functional units are provided in an input / output component called a magnetic head.

The magnetic head and the medium have a function of moving relatively, writing magnetic information at an arbitrary position on the medium, and electrically reproducing the magnetic information as necessary. Taking the magnetic disk device as an example, the magnetic head is composed of a writing unit 21 for reading magnetic information and a reproducing unit 22 for reading magnetic information, as shown in FIG. 2, for example. The writing section includes a coil 26 and magnetic poles 27 and 28 which wrap the coil 26 up and down and are magnetically coupled.
Consists of The reproducing unit 22 includes a magnetoresistive element 23
And an electrode 29 for supplying a constant current to the element and detecting a resistance change. A magnetic shield layer 28 (also used as a write magnetic pole) is provided between the write unit and the read unit. These functional units are formed on the magnetic head main body 30 with the base layer 24 interposed therebetween.

In the example of FIG. 2, the electromagnetic conversion effect is used for recording and the magnetoresistive effect is used for reproduction. However, by detecting the electromagnetic induction current induced in the coil provided in the writing section, the magnetic information can be also obtained. Reproduction is possible. In this case, recording and reproduction can be performed by one functional unit.

[0005] The performance of a storage device is determined by the speed and storage capacity during input / output operations, and it is essential to shorten the access time and increase the capacity in order to increase product competitiveness. In recent years, storage devices have been reduced in size due to demands for lighter, thinner and smaller information devices. In order to satisfy these demands, a lot of magnetic information is written in a single recording medium,
At the same time, development of a magnetic storage device that can reproduce data has become important.

[0006] In order to satisfy this demand, it is necessary to increase the recording density of the apparatus. In order to realize high-density recording, it is necessary to reduce the size of a magnetic domain serving as magnetic information. This can be realized by increasing the frequency (write frequency) of the write current flowing through the coil 26 shown in FIG. 2 and reducing the width of the write magnetic pole 27.

[0007]

According to our studies,
By setting the magnetic pole width to 2.5 μm and the writing frequency to about 90 MHz, a storage density of ² Gb / in ² class could be realized. However, it has been clarified that if further densification is promoted, the following problems will occur, and the densification will be limited.

Conventionally, a magnetic film called an in-plane medium whose magnetization direction is in-plane is used for a recording medium. In the case of an in-plane medium, the magnetization mainly exists at the boundary between magnetic domains, and the presence can be read out by detecting the magnetic field intensity. Since the magnetization is concentrated and distributed, the signal output at this time has a Gaussian waveform. For this reason, the frequency band included in the signal is narrow, and the signal quality deterioration due to the adjacent signal is small. For this reason, it has a feature that the subsequent signal processing is easy.

However, when high-density recording is promoted on an in-plane medium, a problem due to thermal fluctuation of magnetization cannot be avoided.
The thermal fluctuation is caused by the fact that the magnetization in the recording medium fluctuates due to heat, and the magnetic domain becomes finer and the influence of the demagnetizing field from the adjacent magnetic domain becomes remarkable, so that the magnetization direction becomes unstable.

[0010] According to our experiments, about 4 mm in the circumferential direction of the medium.
It has been confirmed that when the density is increased to about 00 kBPI (the number of bits per unit inch) and about 26 kTPI (the number of tracks per unit inch) in the radial direction of the medium, the magnetic domain may disappear due to the thermal fluctuation phenomenon. .

[0011] There is perpendicular magnetic recording as a technique for solving this. In perpendicular magnetic recording, a demagnetizing field from an adjacent magnetic domain acts in a direction to reduce the fluctuation width of magnetization due to thermal fluctuation. Therefore, even if the magnetic domain is increased in density, the phenomenon of disappearance of the magnetic domain due to thermal fluctuation hardly occurs. For this reason, perpendicular magnetic recording is considered as a future high-density recording technology.

However, in perpendicular magnetic recording, magnetization is distributed on the medium surface. Therefore, when reading is performed using a conventional reproducing device that detects the magnetic field intensity, a trapezoidal signal (dipulse) depending on the magnetic domain width is detected. . A trapezoidal signal has a wide band, so that signal processing becomes complicated. Therefore, processing using a complicated electric circuit is required. Therefore, a problem arises in realizing an inexpensive and high-speed apparatus, which has been a reason for delaying the practical use of perpendicular magnetic recording. As a result of this,
A high-density recording device could not be developed.

The above problem can be solved if the reproduction signal from the perpendicular magnetization film has a Gaussian waveform. The purpose of the present invention is
It is an object of the present invention to disclose a novel reproducing means for making a reproduction signal from a perpendicular magnetization film a Gaussian wave shape. Accordingly, a high-speed and high-density recording device using the perpendicular magnetic recording method is made possible.

[0014]

In order to achieve the above object, the present invention uses the following means.

First, a medium having an easy axis of magnetization in a direction perpendicular to the film surface was used as a recording medium, and at least a function of writing information and a function of reproducing information were provided. In particular, the recorded information from the perpendicular magnetization film was reproduced by a reproducing means having a structure in which two spin valve elements having a difference of about 180 degrees in the magnetization direction of the fixed layer were stacked.

The fixed layers of the two stacked spin valve elements were formed of an antiferromagnetic film, and each had a blocking temperature difference of 20 ° C. or more.

In addition, the fixed layers of the two spin-valve elements are formed of a high coercive force film, and each coercive force has a difference of 100 Oe or more.

The current terminal of the first spin-valve element composed of the first functional thin film and the current terminal of the second spin-valve element composed of the second functional thin film are shared.

In addition, the first spin valve element and the second spin valve element were kept in an electrically insulated state, their outputs were connected in a differential relationship, and current was supplied.

In the above case, the first spin valve element and the second spin valve element have a dual spin valve element structure in which a single-layer oxide antiferromagnetic film is interposed.

The above reproducing means is provided on the magnetic head slider, and a part thereof is provided on at least a sliding surface approaching the surface of the perpendicular magnetic recording medium.

A soft magnetic material pattern is provided at a position close to the reproducing means and at a distance from the sliding surface. Thus, a magnetic path from the first spin valve element to the second spin valve element was realized.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIG. 2A is a schematic diagram of a reproducing unit (corresponding to the reproducing function unit 22 shown in FIG. 2). The reproducing section includes a magnetoresistive element 32 and an electrode 31. In the case of the present invention, a giant magnetoresistance effect element or a conventional magnetoresistance effect element can be applied to the magnetoresistance effect element 32. In this embodiment, an example using a giant magnetoresistance effect element will be described.

FIG. 2B is a sectional view taken along line α in FIG.
(C) shows a cross-sectional structure taken along line β. Describing the structure in order, a first giant magnetoresistive element 33 and a second giant magnetoresistive element 34 are stacked, and a nonmagnetic film 36 is provided between them. The soft magnetic layer constituting these giant magnetoresistive elements was made into a single magnetic domain, and magnet patterns 35 having a high coercive force were provided at both ends for the purpose of aligning the magnetization directions in one direction. The magnetization direction of the magnet pattern was parallel to the line α as in the related art.
The electrode 31 exists on the magnet pattern 35 and
The configuration is such that currents in the same direction can flow through the two giant magnetoresistive elements.

In the above structure, the novelty is that two functional thin films corresponding to the giant magnetoresistive element are stacked and that a common electrode is connected to these two functional thin films. is there.

The resistance of each functional thin film changes depending on the magnetic field strength (vertical magnetic field component: a magnetic field component parallel to the line β shown in FIG. 1) at the position where the functional thin film exists. This change can be detected as a change in voltage across both ends by passing a constant current through the functional thin film. Alternatively, a change in current can be detected by connecting a constant voltage source. When a functional thin film is provided at a spatially separated position, the magnetic field strength at a spatially separated position can be measured simultaneously. By detecting this difference in magnetic field strength as an output difference, a magnetic field gradient at a spatially separated position can be obtained.

First, in order to detect a magnetic field intensity difference at a distant position, in this embodiment, each of the two giant magnetoresistive elements has a spin valve element configuration. A specific structure will be described with reference to FIG. First, a base film (Hf: 5
nm) 41, and a soft magnetic film (free layer: Ni)
Fe: 6 nm)) 42, non-magnetic film (Cu: 3 nm)) 43,
A magnetization fixed layer (pin layer: NiFe: 3 nm) 44 and an antiferromagnetic film (Fe-Mn: 10 nm) are laminated, and a first spin valve element (giant magnetoresistive element in a broad sense or a functional thin film) is formed from these layers. 34 were constructed. Similarly, for the second spin valve element 33, the base film (Hf: 5 nm) 4
6, soft magnetic film (free layer: NiFe: 6 nm)) 47, non-magnetic film (Cu: 3 nm)) 48, magnetization fixed layer (pin layer: N)
iFe: 3 nm) 49, antiferromagnetic film (Fe-Mn: 10)
Hf with a thickness of 5 nm as the protective layer 51.
Were laminated.

Further, in order to detect a difference in magnetic field strength (magnetic field gradient) with the above configuration, the magnetization fixed layer 44 forming a part of the first element 34 and the magnetization fixed layer forming a part of the second element 33 are fixed. The magnetization direction of the layer 49 has a difference of about 180 degrees. In order to realize this, the blocking temperature of the antiferromagnetic films constituting each of the two spin valve elements is given a difference of 20 ° C. or more. The magnetization of the fixed layer changes the magnetization direction by a predetermined axis (usually a line β shown in FIG. 1) by an exchange coupling effect from the antiferromagnetic film.
Parallel) or antiparallel. The definition of parallel or antiparallel can be determined by externally applying a magnetic field. This exchange coupling action is temperature-dependent and has a property of disappearing at a predetermined value or more. This temperature is called the blocking temperature.

As described above, above the blocking temperature, the magnetization of the fixed layer cannot be specified. Therefore, even when the spin valve elements are stacked, if there is a difference between the blocking temperatures of the antiferromagnetic films constituting each spin valve element, the magnetization of the fixed layer is sequentially specified by controlling the temperature when an external magnetic field is applied. can do. The blocking temperature differs for each antiferromagnetic film material such as NiFe, NiMn, IrMn, and NiO, and can be changed by changing the composition and film forming conditions even for the same material. This change can be controlled, and it is easy to provide a blocking temperature difference of 20 ° C. or more. If there was a temperature difference of 20 ° C. or more, there was no problem in the magnetization operation for inverting the magnetization of the fixed layer by 180 degrees. For the above reason, the magnetization directions of the magnetization fixed layer 44 forming a part of the first element 34 and the magnetization fixed layer 49 forming a part of the second element 33 are changed by approximately 180 degrees (assumed to be antiparallel). It can be understood that it is possible.

Next, the reason why the magnetic field intensity difference can be detected by changing the magnetization directions of the magnetization fixed layer of the first element and the magnetization fixed layer of the second element by approximately 180 degrees (antiparallel) will be described.
FIG. 6A shows the magnetization state of one spin valve element (giant magnetoresistive element in a broad sense). Fixed layer (pin layer) 6
The magnetization of No. 7 is antiparallel to the Y axis (vertical magnetic field direction). The intermediate layer 66 is a non-magnetic material (Cu). On this, a soft magnetic layer (free layer) 65 having a magnetization state parallel to the X axis is located. When a magnetic field (vertical magnetic field component: perpendicular to the recording medium surface) 68 is applied to this film, the magnetization 91 rotates in the α direction or the β direction depending on the direction.
When the magnetization 91 rotates in the α direction, it approaches a state parallel to the magnetization direction of the fixed layer 67. Conversely, when it rotates in the β direction, it approaches an anti-parallel state. According to the principle of the spin valve element, the electric resistance is small in the parallel state and large in the antiparallel state.

As shown in FIG. 3B, two spin valve elements having an intermediate layer 66-1 and an intermediate layer 66-2 are stacked (in the figure, the overlap is schematically shown), and the first element is formed. Consider a state in which a magnetic field 69 is applied and a magnetic field 70 in the opposite direction is applied to the second element. As is apparent from the figure, the soft magnetic layer 6
The magnetization of 5-1 rotates in the β direction, while the magnetization of the soft magnetic layer 65-2 rotates in the α direction. Soft magnetic layer 65-
1 and the magnetization direction of the fixed layer 67-1 are in an antiparallel state, and the magnetization direction of the soft magnetic layer 65-2 and the magnetization direction of the fixed
2 is parallel to the magnetization direction. Therefore, if the polarities of the external magnetic fields 69 and 70 are simply different, only the magnitude of the resistance is generated in each of the elements, and there is no change in the total resistance. (Strictly speaking, a slight change occurs due to the element variation.) ).

However, as shown in FIG.
When the magnetization directions of 7-1 and the fixed layer 67-2 are antiparallel, when the magnetic field 69 is applied to the first element and the magnetic field 70 in the opposite direction is applied to the second element, the magnetization becomes By rotating in the same way, both the magnetization directions of the fixed layers 67-1 and 67-2 are in an anti-parallel state (high resistance).
The total resistance of the two elements is large. In addition, the external magnetic field 6
9. When the external magnetic field 70 is in the opposite direction, the magnetization of the soft magnetic layer rotates in the opposite direction to that in the above example, so that the electrical resistance is reduced in both cases.

However, if the magnetic field 69 and the magnetic field 70 are both parallel, the magnetizations of the soft magnetic layers 65-1 and 65-2 rotate in the same direction. , Both anti-parallel and parallel states. For this reason,
No change in overall resistance occurs. As described above, by making the magnetization directions of the fixed layer magnetization of the first element and the fixed layer magnetization of the second element antiparallel, a resistance change occurs only when an opposite magnetic field is applied to both elements. be able to.

If there is a magnetic field gradient between the two elements,
The state is the same as when the difference between the external magnetic fields is applied to the two elements described above. When this difference occurs, a change occurs in the total resistance of the two elements for the reason described above. It is apparent from the above reason that this change can be detected as a change in current or voltage.

The feature of this embodiment is that the magnetization direction of the fixed layer is made antiparallel (about 180 degrees). Other methods for defining the magnetization direction of the fixed layer include an α-Fe ₂ O ₃ film, a Co
There is a method using exchange coupling between a high coercivity film such as a Pt film and a ferromagnetic film. In this case, a high coercive force film is laminated instead of the antiferromagnetic films 45 and 50 (laminated at the same position). In the case of the present invention, since two elements are stacked, the coercive force of each element has a difference of 100 Oe or more. If the coercive force is different, the magnetization direction can be defined while sequentially decreasing the magnetization magnetic field. Thereby, the magnetization direction of the fixed layer can be set arbitrarily (in the case of the present invention, antiparallel). The larger the difference in coercive force, the easier the magnetization. However, if there is a difference of about 100 Oe or more, there was no practical problem. It is well known that a difference in coercive force can be controlled by managing a material, a film composition, a film forming temperature, a film forming rate, and the like. Therefore, by the above operation, the magnetization direction of the fixed layer can be set to be antiparallel, and can be applied to the present invention.

The magnetic field gradient detecting means composed of the two functional thin films is formed on the conventional magnetic head slider 2 shown in FIG. This magnetic head slider 2 includes:
It goes without saying that the writing means is provided by a predetermined means. As the recording medium 11, a perpendicular medium having an easy axis of magnetization in a direction perpendicular to the film surface was used. The magnetic head slider 2 was supported by the suspension member 7 and the arm 4. The rotary actuator 3 was used for positioning the magnetic head slider 2 and the recording medium. Others
Although not shown in the drawing, the recording apparatus of the present invention was completed using a motor for rotating the recording medium, a circuit board for processing electric signals, an electric circuit for controlling the entire apparatus, and the like. By applying the magnetic field gradient detecting means constituting the main part of the present invention, the reproduced signal has a Gaussian waveform even when a perpendicular magnetization film is used as the recording medium. For this reason, the same signal processing circuit as in the case where the in-plane magnetized film was used as the recording medium could be used.

Since this signal processing circuit has a small number of signal detection points, it has a feature that the circuit scale is small and the speed is excellent. Therefore, even when the recording density is increased, there is no loss of processing time in a portion related to signal processing.

The above effect can be obtained for the first time by the present invention. This can be realized by applying a magnetic field gradient detecting means in which two functional thin films are stacked to a means for reproducing magnetic information from a perpendicular magnetization film. It becomes.

To further clarify this point, description will be made with reference to FIG. FIG. 7A shows a cross section (a cross section in a plane parallel to the line β in FIG. 1) of the magnetic field gradient detecting means and the perpendicular magnetization film in which two functional thin films are stacked. In the perpendicular magnetization film 11,
At the place where the information “1” exists, the magnetization state is inverted from the upward 81 to the downward magnetization state 82. Therefore, information can be read from the presence of the magnetization reversal 80.

Considering the case where the first functional thin film 33 and the second functional thin film 34 are located on this medium and directly above the magnetization reversal 80, the magnetic flux is generated from each magnetic domain in the direction shown in the figure. This magnetic flux is generated by two functional thin films (more specifically,
To the soft magnetic layer constituting the spin valve element).
Since the left and right magnetization states are antiparallel with respect to the magnetization reversal 80, the magnetic fields acting on the two functional thin films are also antiparallel. That is, it is understood that a magnetic field difference occurs between the two functional thin films. For this reason, a change occurs in the total resistance of the two functional thin films for the reasons described above, and this change can be detected as an electric signal. Needless to say, when the directions of the magnetizations 81 and 82 are reversed, the directions of magnetic fluxes acting on the two functional thin films are reversed. For this reason, a resistance change (resistance increase or decrease) opposite to the above occurs.

However, when there is no magnetization reversal immediately below the first functional thin film 65 and the second functional thin film 67 as shown in FIG. 7B, the two functional thin films are equal, and Since only a weak magnetic flux (a leakage magnetic field is reduced by a demagnetizing field from the magnetic domain itself) is introduced, no electric signal is generated.

As described above, the resistance of the two functional thin films changes only when a magnetic field difference from the medium, that is, a magnetic field gradient occurs. In addition, since this change changes into a large resistance and a small resistance depending on the magnetization state at the magnetization reversal position, a single-pulse electric signal is obtained. Due to this feature, signal processing similar to that of the related art can be performed using the perpendicular magnetization film.

The above embodiment has been described based on the structure of a general spin valve element. Needless to say, the present invention can be realized in other spin valve element configurations.

Other structures for detecting the magnetic field gradient created by a vertical magnetic field include H. NEALBERTRA.
M), pages 194 to 199 of THEORY OF MAGNETIC RECORDING. This structure includes two magnetoresistive elements 61, as shown in FIG.
63 are laminated with an insulating layer or a high resistance film 62 interposed therebetween, and two magnetoresistive effect elements 61,
An opening angle is generated in the magnetization of 63. This opening angle is
Determined by the amount of current, element width, distance between magnetoresistive elements, and the like. This can easily be inferred from the theory of the soft magnetic bias film (SAL) type magnetoresistance effect element.

Although the above configuration is simple, there is a problem that the sensitivity is low because the magnetoresistive effect is used for the functional thin film. Therefore, it is necessary to use a perpendicular magnetization film at a recording density of 1
At 0 Gb / in ² or more, insufficient reproduction output occurred. Also,
The opening angle of the magnetization does not cause any problem in the symmetry of the amplitude (there is almost no difference between the positive amplitude and the negative amplitude), but the symmetry of the pulse with respect to the time axis changes. This phenomenon is not described in the above disclosed technology. The problem of the symmetry of the pulse with respect to the time axis is caused by the property that the sensitivities of the two magnetoresistive elements change in opposite directions (high and low) depending on the inclination angle of magnetization (open angle of magnetization). When this phenomenon occurs, when the magnetic information is located on the high-sensitivity magnetoresistive element side, a pulse with a widened skirt is reproduced, and in the opposite case,
A pulse with a narrow tail is reproduced.

In high-density recording, interference with adjacent signals becomes remarkable. At this time, if nonlinear distortion occurs in the signal, subsequent signal reproduction processing cannot be performed. In order to avoid this, the sensitivity of the two magnetoresistive elements should be the same. However, there is a limit to the tolerance at the time of manufacturing and the accuracy of the flowing current (including control for external factors such as temperature), and there is a problem. Had occurred.

Since the present invention uses a spin valve element, there is no problem in sensitivity. In the spin valve structure, since the fixed layer magnetization is defined in one direction by the antiferromagnetic film or the like, the problem of asymmetry does not occur. Such an excellent structure is not derived from the above prior art.

Another embodiment in which a good reproduction function from a perpendicular magnetization film is realized by using two spin valve elements will be described below. In this embodiment, the first spin valve element and the second spin valve element are kept in an electrically insulated state. Therefore, as shown in FIG. 5A, the electrodes 71, 73 and 72, 74 are connected to the respective spin valve elements. Needless to say, these electrodes are electrically insulated.

As shown in FIG. 5 (b), an oxide antiferromagnetic film 53 is interposed between the two spin valve elements in order to keep the two spin valve elements in an electrically insulated state. NiFe alloy films 44 and 49 having a thickness of 6 nm are formed above and below this.
To form a fixed layer. Further outside, 3 nm thick Cu intermediate layers (non-magnetic layers) 43 and 48 and 3 nm thick NiFe alloy films 42 and 47 were applied. The NiFe alloy films 42 and 47 play a role of a free layer in the spin valve element. In order to improve the function as a free layer,
Further, an Hf film having a thickness of 5 nm was applied to the outside. This Hf film also has a function as a protective film.

As described above, each electrode may be insulated by the oxide antiferromagnetic film 53 in order to make the first spin valve element and the second spin valve element electrically insulated. In this case, the process is simplified. Incidentally, in the above configuration, since the magnetization of the fixed layer is defined by the common material, it is difficult to make the magnetization directions antiparallel between the first element and the second element. For this reason, the electrodes are insulated. Even with such a configuration, as shown in FIG. 5C, the output electrodes 72 and 74 and the output electrodes 71 and 73 are connected to amplifier circuits having different polarities, and so-called differential processing for combining the respective outputs is performed. By doing so, it becomes possible to reproduce recorded information from the perpendicular magnetization film. The reason for this can be explained because, in the above configuration, an output is finally obtained only when outputs having different polarities are detected in the two elements. This state is equivalent to the state shown in FIG. 7, and for this reason, the perpendicular magnetization film can be reproduced.

The present embodiment is characterized in that, even if a thermal fluctuation occurs, the effect is generated in each element in common, and this effect can be removed by the operation processing circuit. From this feature, it is possible to apply to a contact recording method in which the disturbance is expected to increase although the number of electrodes increases.

A reproducing function is realized by providing any one of the above-mentioned reproducing means on the magnetic head slider and at least a part thereof on the sliding surface approaching the surface of the perpendicular magnetic recording medium. At this time, as shown in FIG. 8, a soft magnetic material pattern 38 was provided at a position close to the first spin valve elements 33 and 34 and away from the sliding surface. By providing the soft magnetic pattern 38, a magnetic path is provided between the spin valve element 33 and the spin valve element 34. This magnetic path is effective in guiding magnetic fluxes from the magnetization 81 and the magnetization 82 in the recording medium 11 to the spin valve elements 33 and 34 with high efficiency. In the absence of this pattern, a large proportion of the magnetic flux flows into an adjacent element in a portion where the two spin valve elements are parallel. However, if there is a magnetic path at a portion far from the medium surface, the magnetic flux flows toward this magnetic path. As a result, as a result, magnetic flux flows in many regions of the element, and a highly efficient output is obtained.

[0053]

According to the present invention described above, even when a perpendicular magnetization film is used as a recording medium, a reproduced signal has a Gaussian waveform. From this effect, it is possible to use the same signal processing circuit as in the case where the in-plane magnetic film is used as the recording medium. Since this signal processing circuit has a small number of signal detection points, it has features that the circuit scale is small and the speed is excellent. Therefore, even when the recording density is increased, there is no loss of processing time in a portion related to signal processing.

The above-mentioned effect can be obtained for the first time by the present invention, and can be realized by applying a detecting means in which two spin valve elements are stacked to a means for reproducing magnetic information from a perpendicular magnetization film. It is. From the above effects, an ultra-high-density recording apparatus using a perpendicular magnetization film and having a recording density of 10 Gb / in ² or more has become possible.

[Brief description of the drawings]

FIG. 1 is a perspective view and a cross-sectional view showing a configuration of a reproducing unit according to an embodiment of the present invention.

FIG. 2 is a perspective view of a reproducing unit and a recording unit in a conventional magnetic head.

FIG. 3 is a plan view of a magnetic recording apparatus using the present invention.

FIG. 4 is an explanatory diagram of a conventional technique using dual MR.

FIG. 5 is a perspective view, a sectional view, and a circuit diagram showing a configuration of a reproducing unit according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing the operation principle of the reproducing means of the present invention.

FIG. 7 is an explanatory diagram showing the operation principle of the reproducing means according to one embodiment of the present invention.

FIG. 8 is an explanatory diagram showing an operation principle of a reproducing unit according to another embodiment of the present invention.

[Explanation of symbols]

2 magnetic head slider, 3 rotary actuator, 4 arm, 7 suspension, 11 recording medium, 21 recording unit (writing unit), 22 reading unit (reproducing unit), 23 magnetoresistive element, 24 ... underlayer,
25: lower core or lower magnetic pole, 26: coil, 27
... upper core or upper magnetic pole, 28 ... shield layer, 29
... electrodes, 30 ... substrate (slider material), 33,34 ... spin valve elements, 41,46,51 ... underlying film (protective film),
42, 47: soft magnetic film (free layer), 43, 48: intermediate layer (nonmagnetic layer), 44, 49: fixed layer (magnetic layer), 4
5, 50: antiferromagnetic layer (high coercive force film), 53: oxide antiferromagnetic film, 61, 63: magnetoresistance effect film, 62: insulating layer (high resistance film), 71, 72, 73, 74 ... Electrodes, 80 ...
Magnetization transition region, 81, 82 ... magnetization.

Claims (8)

[Claims] 1. A recording apparatus using a recording medium having an easy axis of magnetization in a direction perpendicular to a film surface and having at least a function of writing information and a function of reproducing information, wherein a magnetization direction of a fixed layer is about 180 degrees. A perpendicular magnetic recording apparatus using a reproducing means having a structure in which two different spin valve elements are stacked. 2. The fixed layer of the two stacked spin valve elements is formed of an antiferromagnetic film, and each antiferromagnetic film has a blocking temperature difference of 20 ° C. or more. 2. The perpendicular magnetic recording apparatus according to claim 1, wherein: 3. A method according to claim 1, wherein the fixed layers of the two spin valve elements are formed of a high coercivity film, and a coercive force difference of 100 Oe or more is set in each high coercivity film. 2. The perpendicular magnetic recording device according to claim 1. 4. The device according to claim 1, wherein the current terminal of the first spin valve element and the current terminal of the second spin valve element are shared. Perpendicular magnetic recording device. 5. A first spin valve element and a second spin valve element are electrically insulated, and at least reproduce information from a perpendicular recording medium by differentially outputting their outputs. A perpendicular magnetic recording device comprising a reproducing means having a function. 6. The vertical spin valve element according to claim 5, wherein said first spin valve element and said second spin valve element have a dual-type spin valve element structure sandwiching an oxide antiferromagnetic film. Magnetic recording device. 7. The magnetic head slider according to claim 1, wherein said reproducing means is provided on a magnetic head slider, and a part thereof is provided on at least a sliding surface approaching a surface of a perpendicular magnetic recording medium. Perpendicular magnetic recording device. 8. A soft magnetic pattern is provided at a position close to the reproducing means and at a distance from the sliding surface, and the first and second spin valve elements are moved by the soft magnetic pattern. 6. The perpendicular magnetic recording apparatus according to claim 1, wherein a function of a magnetic path to the magnetic recording medium is realized.