JP3239578B2 - Magnetic playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses SPM technology to detect a force or a gradient of a force due to a magnetic interaction between a magnetic probe and a magnetic recording medium, thereby obtaining high-density recorded information. The present invention relates to a magnetic reproducing device that performs reproduction.

[0002]

2. Description of the Related Art In recent years, demands for high-speed and large-capacity storage devices have been increasing with the increase in the amount of information. In response to such demands, by increasing the areal recording density in storage devices. Further densification is underway. As a conventional storage device, a storage device using magnetic recording or optical recording magnetic recording is known. As a storage device using magnetic recording, there is a magnetic disk device that performs recording or reproduction using an inductive head or an MR head. In this magnetic disk drive, studies are being made to increase the recording density by controlling the flying height of the flying head slider from the recording medium to 0.1 μm or less. However, such a low-flying technique in the submicron region has a problem of reliability such as contact with a medium and destruction of data, and a track width of recorded information is more than ten due to a reduction in signal S / N. It is said that the limit is about μm to several μm. In the reproducing method using the light storage device, the resolution is determined by the spot size determined by the wavelength of the light source and the numerical aperture of the objective lens.

In recent years, scanning probe microscopes (SPMs) have been used in the field of material microstructure evaluation.
icroscope) has attracted attention. This scanning probe microscope (SPM) is a scanning tunneling microscope (STM:
Scanning Tunneling Microscope, Atomic Force Microscope (AFM), Magnetic Force Microscope (MFM) and the like are generic names. The STM uses a tunnel current between a small probe and the sample surface to observe the structure of the sample surface in the atomic order, and the AFM uses a force between atoms between the small probe and the sample surface to sample the surface of the sample. Observation of the structure in atomic order, MFM uses a probe as a magnetic substance,
This is to observe the magnetization state of a minute region using the force of magnetic interaction (magnetic force) between the probe and the sample.

For example, the SPM has a configuration shown in FIG. 9 or FIG. 10 schematically showing a signal detection system. The configuration shown in FIG. 9 is a “static mode”
In the figure, 31 is a sample to be observed,
Reference numeral 32 denotes a support piece (cantilever) having a base end supported and provided with a probe 33 at the distal end, reference numeral 34 denotes a displacement measuring means for measuring the amount of displacement of the support piece 32, and reference numeral 36 denotes X-axis, Y-axis, and Z-axis An axially movable actuator, 35 indicates an amplifier. The sample 31 is mounted on an actuator 36 constituted by, for example, a piezoelectric element movable in three axial directions, and the support piece 32 is arranged so that the probe 33 comes to a position close to the sample 31. When a force acts between the probe 33 and the sample 31, the support piece 32 is distorted in accordance with the force, and the amount of distortion of the support piece 32 is observed by the displacement measuring means 34, and the output Uo from the displacement measuring means 34 And steady state U
is compared by the amplifier 35, and the change from the steady state is determined by the actuator 36 which is a drive mechanism of the Z axis (height direction).
To make the amount of distortion of the support piece 32 zero (or constant), and the feedback signal Uz
By observing, the force distribution on the sample surface is measured. The displacement measuring means 34 for measuring the displacement of the support piece 32
Examples of the method include a method using a tunnel current, a method using laser interference, an optical lever method, and a method for detecting a change in capacitance. These methods can be used.

On the other hand, the configuration shown in FIG. 10 is called a "dynamic mode". In the configuration shown in FIG. 9, a phase meter 37 for detecting a phase change of the support piece 32 and a resonance frequency A support vibrating means 38, which is made of a piezoelectric element or the like to vibrate at a constant frequency nearby, is added. Note that the support vibrating means 38 includes a driving means 39 of the support piece 32 and a vibrating means 40. When the gradient of the force acting on the probe 33 changes,
The resonance frequency of the support piece 32 changes, and the vibration amplitude or phase change of the support piece 32 accompanying the change in the resonance frequency is detected by the displacement measuring means 34 and the phase meter 37, and the change from the steady state Us is transmitted to the actuator 36. By feeding back the detection signal Uf to be constant and observing the feedback signal Uz, the gradient of the force on the sample surface is measured. In this case, in the configuration of FIG. 10, phase detection by laser interference is used.

[0006] Recently, a storage device that performs recording and reproduction on a magnetic recording medium by applying the above-described SPM technology has been studied. This type of storage device magnetizes a minute magnetic probe and records on a magnetic medium using a magnetic field induced by the magnetization of the magnetic probe, while detecting a magnetic field distribution or a change in magnetic flux due to the magnetization on the medium. It is to play. By the way, in this type of recording / reproducing apparatus, a magnetic probe scans a recording medium at a constant interval, and a support piece generated by a force due to a magnetic interaction between a recording bit recorded on the recording medium and the magnetic probe. The displacement amount (distortion amount) is detected by the displacement measuring means, and feedback control is performed so as to keep the distance between the recording medium and the magnetic probe constant according to a signal from the displacement measuring means. In this case,
It is necessary to add a support piece (for example, a cantilever) for adjusting the distance between the recording medium and the magnetic probe.

[0007]

However, according to the magnetic storage device using the SPM technique as described above, the recording medium and the magnetic probe are kept constant at a very close distance of several hundred nanometers or less. Although it is necessary to sag, it is extremely difficult to maintain such a small interval. In other words, maintaining a small distance between the recording medium and the magnetic probe means that a change in magnetic force due to a change in the distance between the magnetic recording medium and the magnetic probe is caused by a change in the magnetization state on the magnetic recording medium. It is a necessary condition to avoid being superimposed on the change in magnetic force, moving at a relatively high speed with the magnetic probe, for example, when performing recording or reproduction on a disk-shaped recording medium, In particular, there has been a problem that it is difficult to maintain the minute interval. Further, like the magnetic disk device, there is a possibility that the magnetic probe comes into contact with the recording medium, and there is a problem of reliability as a storage device.
When a small probe is provided at the tip of a support piece (cantilever) that is easily bent by the force to be measured,
It is even more serious. Furthermore, when the distance between the recording medium and the magnetic probe approaches the nanometer order, the magnetic probe is affected not only by the force of magnetic interaction but also by the atomic force based on the surface shape of the recording medium. There is also a problem that it becomes difficult to separate noise by a signal and a surface shape. Therefore, the present invention uses SPM technology to detect a force or a gradient of force due to a magnetic interaction between a magnetic probe and a magnetic recording medium, reproduce information recorded at high density, It is intended to provide a magnetic reproducing apparatus capable of reproducing a recording signal without being affected by variations in the distance between the probe and the probe, and reproducing the recording signal without being affected by the surface shape of the recording medium.

[0008]

In order to achieve the above object, a magnetic reproducing apparatus according to the present invention comprises: a support piece formed to have a predetermined length and supported at one end in a longitudinal direction; A magnetic probe supported on the support piece of the magnetic recording medium and disposed opposite to the magnetic recording medium; a displacement measuring means for detecting a displacement of the support piece in a direction approaching or moving away from the magnetic recording medium; And a magnetic yoke interposed between the magnetic recording medium and a magnetic probe.

Further, in the magnetic reproducing apparatus according to the present invention, the magnetic yoke is supported by a non-magnetic core, and a support piece at one end in the longitudinal direction is supported by the non-magnetic core. . Further, the magnetic reproducing apparatus according to the present invention is characterized in that a displacement amount of the support piece is controlled to 0 or a constant value according to a detection value of the displacement measuring means. Further, the magnetic reproducing apparatus according to the present invention is characterized in that the magnetic reproducing apparatus has a vibrating means for vibrating the support piece at a constant frequency.

[0010]

In such a magnetic reproducing apparatus, a magnetic flux induced by a magnetization pattern recorded on a magnetic recording medium is guided to a magnetic probe via a magnetic yoke made of a thin-film magnetic material having a high magnetic permeability. . When a magnetic force acts on the magnetic probe, a support piece for supporting the magnetic probe, such as a cantilever, is distorted in a direction approaching or moving away from the magnetic recording medium according to the magnetic force, and the displacement of the cantilever is measured by displacement measuring means. Thereby, the magnetization state recorded on the magnetic recording medium is detected, and the recorded information is reproduced. In this case, since the magnetic yoke made of a thin-film magnetic material is provided between the magnetic recording medium and the magnetic probe, the magnetic probe can be used even if the distance between the magnetic recording medium and the magnetic yoke slightly changes. The change in the felt magnetic force is very small, and the magnetic force acting on the magnetic probe due to the magnetization reversal of the recording signal changes from attractive force to repulsive force or from repulsive force to attractive force. Hardly affected by magnetic force change. Also, since the magnetic yoke disposed between the magnetic recording medium and the magnetic probe serves as a protective film for the magnetic probe, the magnetic probe does not come into direct contact with the magnetic recording medium. And there is less danger of damaging the cantilever. Furthermore, if the length of the magnetic yoke is set to be equal to or greater than the distance at which the atomic force acts, the magnetic probe can detect only the magnetic force without being affected by the atomic force, and the surface shape of the magnetic recording medium can be used for reproducing signals. The effect can be reduced. Therefore, even when reproducing information recorded at a high density using the SPM technique, the displacement of the support piece is detected at a high resolution by the displacement measuring means, thereby affecting the variation in the distance between the recording medium and the probe. Thus, it is possible to reproduce the recording signal without being affected by the surface shape of the recording medium.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing a magnetic reproducing apparatus, and FIG.
(A), (b) and (c) are perspective views showing various cantilevers (support pieces), and FIG. 3 is a block diagram of an optical system showing an example of heterodyne interferometry. As shown in FIG. 1, a magnetic reproducing apparatus 1 according to the present embodiment includes a non-magnetic core 3 disposed so as to face a magnetic recording medium 2, and a base end portion provided on the non-magnetic core 3 via a support member 4. A cantilever (supporting piece) 5 supporting the magnetic recording medium 2, a magnetic probe 6 attached to a tip of the cantilever 5 so as to face the magnetic recording medium 2, a displacement measuring means 7 for detecting a displacement of the cantilever 5,
A magnetic yoke 8 made of a thin-film magnetic material is provided in the nonmagnetic core 3 and between the magnetic recording medium 2 and the magnetic probe 6.

The magnetic yoke 8 is formed by depositing sendust in the non-magnetic core 3 into a film having a thickness of 1 μm by sputtering.
It is formed into a stripe shape having a width of 1 μm by ion milling and then polished to a length of 20 μm. The magnetic yoke 8 may be made of a film having a high magnetic permeability and a small coercive force, such as Permalloy, Co-Zr-Nb, Co-
It may be made of a material such as Zr-Pd, and when permalloy is used, the film thickness can be reduced to about 0.05 μm. Further, the magnetic yoke 8 is disposed such that a tip end thereof is in contact with or close to the magnetic recording medium 2, and the magnetic yoke 8 is magnetized by a leakage magnetic field from a recording bit recorded on the magnetic recording medium 2, Further, the magnetic probe 6 has a function of applying a magnetic interaction force (magnetic force) to the magnetic probe 6 by a magnetic field generated by a magnetic flux from the magnetic yoke 8.

The magnetic probe 6 is formed of a magnetic material and is attached to the tip of a small cantilever 5.
When a magnetic force acts on the magnetic probe 6, the cantilever 5 is distorted according to the magnetic force, and by measuring the displacement of the cantilever 5, the magnetization state recorded on the magnetic recording medium 2 is detected and recorded. Information is reproduced. Also,
The magnetic probe 6 can be manufactured by electrolytic polishing a wire made of a magnetic material such as Fe or Ni, or by using W, Si, SiO ₂ ,
It is manufactured by a method of coating a non-magnetic needle such as Si ₃ N _{4 with} a magnetic material such as Fe, Co, and permalloy by a sputtering method. Further, the sharpness of the tip of the magnetic probe 6 is higher when it has a sharper shape with a smaller radius of curvature, so that the radius of curvature of the tip of the magnetic probe 6 is 100.
nm or less.

The cantilever 5 is made of Si, SiO ₂ ,
It is formed by finely processing a thin film of Si ₃ N ₄ by lithography. The cantilever 5 may be formed integrally with the magnetic probe 6 by electrolytically polishing a metal wire. The shape of the cantilever 5 is a cantilever shape shown in FIG. 2A, a V-shaped beam shape shown in FIG. 2B, or a four-sided shape shown in FIG. Existing shape. The cantilever 5 has a small spring constant (0.01 to 1) so that it can respond to a minute magnetic force.
0N / m), and a high resonance frequency is desired so that the influence of external vibration is reduced.
The cantilever 5 is as light as possible and preferably has a very small size. For this reason, in this embodiment, the length of the cantilever 5 is formed to be about 100 μm. Further, the displacement of the cantilever 5 is detected by the displacement measuring means 7. As a specific method of detecting the displacement of the cantilever 5, a method of detecting a tunnel current, a laser interference method,
In addition to an optical method such as an optical lever method, there is a method of detecting a change in capacitance. In this embodiment, an optical heterodyne interference method is used.

As the displacement measuring means 7 using the optical heterodyne interferometry, for example, as shown in FIG. 3, the light source 1 for generating light of two frequencies slightly shifted in frequency as shown in FIG.
0, a polarizing beam splitter 11 for dividing light of two frequencies into reference light and measurement light, quarter-wave plates 12 and 13
, A mirror 14, a polarizer 15, a photodetector 16, etc., constitute a Michelson-type interferometer, which detects the displacement of the cantilever 5. By using an optical frequency shifter combining a He-Ne laser and an acousto-optic element or a Zeeman effect type laser as the light source 10, linearly polarized lights having slightly shifted frequencies can be obtained. . In such a magnetic reproducing apparatus 1, when light is emitted from the light source 10 to the cantilever 5, the polarized beam splitter 11 separates the reference light toward the mirror 14 and the measurement light toward the cantilever 5, and these lights are separated. Is a quarter wave plate 12,
13, the polarization beam splitter 11 and the mirror 1
4 or the reciprocating passage between the cantilevers 5 makes the polarization plane 90
゜ rotate, and the respective reflected lights are combined again by the polarizing beam splitter 11 as light heading to the photodetector 16. Further, by passing through the polarizer 15 set at 45 ° with respect to the polarization direction, the two lights interfere with each other, and are detected as a beat signal that changes in a sinusoidal manner due to the difference between the frequencies of the two lights. Photoelectrically detected by the detector 16. Further, by measuring the phase change of the beat signal by the photodetector 16, the difference in optical path length between the reference light and the measurement light is obtained. That is, if the phase difference is φ and the optical path length difference between the reference light and the measurement light is L, the relationship of φ = 4πL / λ holds. Here, λ is the wavelength of the light source, and λ = 6
If a 33 nm He-Ne laser is used, a resolution of 0.88 nm can be obtained per 1 ° of phase change.

Further, in such a magnetic reproducing apparatus 1, the magnetic flux induced by the magnetization pattern recorded on the magnetic recording medium 2 passes through the magnetic yoke 8 made of a thin-film magnetic material having a high magnetic permeability. It is led to the probe 6. FIG. 4 shows the result obtained by calculation of how the magnetic flux from the magnetic recording medium 2 changes inside the magnetic yoke 8. FIG. 4 shows the magnetic flux distribution in the magnetic yoke 8, in which a1, a2, a3
Indicates that the distance between the magnetic recording medium 2 and the tip of the magnetic yoke 8 is 10 nm.
Where b1, b2, and b3 represent the distance between the magnetic recording medium 2 and the tip of the magnetic yoke 8 of 100 nm.
Represents the change in the magnetic flux density at the time. The subscripts 1, 2, and 3 indicate that the magnetic yoke 8 has a length of 10 μm each.
m, 20 μm, and 30 μm. As can be seen from FIG. 4, on the magnetic recording medium 2 side of the magnetic yoke 8, the magnetic flux density entering the magnetic yoke 8 is greatly different due to the difference in the distance between the magnetic recording medium 2 and the tip of the magnetic yoke 8. The magnetic flux density increases as the distance between the magnetic yoke 8 and the tip of the magnetic yoke 8 decreases. However, at the end of the magnetic yoke 8 opposite to the magnetic recording medium 2, the difference in magnetic flux density due to the difference in the distance between the magnetic recording medium 2 and the tip of the magnetic yoke 8 is small. That is, when the length of the magnetic yoke 8 is 3
At 0 μm, the difference is reduced from 13.5% to 7.8%. This means that even if the distance between the magnetic recording medium 2 and the magnetic yoke 8 fluctuates to some extent, the magnetic flux felt by the magnetic probe 6 hardly fluctuates.

Therefore, according to the present embodiment, even if the distance between the magnetic recording medium 2 and the magnetic yoke 8 fluctuates slightly, the change in the magnetic force felt by the magnetic probe 6 is very small, and the magnetization reversal of the recording signal is performed. As a result, the magnetic force acting on the magnetic probe 6 changes from attractive force to repulsive force, or from repulsive force to attractive force, so that it is hardly affected by the magnetic force change caused by the distance between the magnetic recording medium 2 and the magnetic yoke 8. Since the magnetic yoke 8 disposed between the magnetic recording medium 2 and the magnetic probe 6 serves as a protective film for the magnetic probe 6,
Is not in direct contact with the magnetic recording medium 2 and the risk of damaging the magnetic probe 6 and the cantilever 5 is small. Further, if the length of the magnetic yoke 8 is set to be equal to or greater than the distance at which the atomic force acts, the magnetic probe 6 can detect only the magnetic force without being affected by the atomic force, and the surface shape of the magnetic recording medium 2 is reduced. The effect on the reproduction signal can be reduced.

As a result, the magnetic reproducing apparatus 1 of this embodiment
According to the structure described above, since the magnetic yoke 8 is arranged between the magnetic recording medium 2 and the magnetic probe 6, even when information recorded at high density is reproduced by using the SPM technique, the magnetic recording is performed. Even if the distance between the medium 2 and the magnetic yoke 8 fluctuates slightly, the fluctuation of the magnetic force felt by the magnetic probe 6 is reduced, and the recording signal can be reproduced without being affected by the fluctuation of the interval between the recording medium and the probe 6. Thus, it is possible to reliably reproduce the signal of the recording bit recorded at high density on the magnetic recording medium 2 without being affected by the surface shape of the recording medium. Further, in this embodiment, since the core portion including the magnetic yoke 8 functions as a protective film for the magnetic probe 6 and the cantilever 5, there is no danger of the magnetic probe 6 and the cantilever 5 colliding with the magnetic recording medium 2, and the reliability is improved. Is improved. Further, since the magnetic force applied to the magnetic probe 6 via the magnetic yoke 8 is hardly affected by the fluctuation of the spacing between the magnetic recording medium 2 and the magnetic yoke 8, the position control of the cantilever 5 or the magnetic recording medium 2 is performed. Without providing a feedback loop, the displacement information of the cantilever 5 from the displacement measuring means 7 can be directly used as a reproduced signal, so that there is no actively driven portion in the head. It becomes possible to make a very simple configuration.

FIGS. 5 and 6 show the reproducing head.
As shown in (1), a configuration in which the magnetic yoke 8 is incorporated in the flying slider 18 may be adopted. 5A is a perspective view of the cantilever 5 provided in the slider 18, and FIG. 5B is a cross-sectional view taken along the line AA in FIG.
5C is a sectional view taken along the line BB in FIG. 5A, and FIG.
FIG. 2A is an enlarged perspective view of a portion C in FIG. In this case, the magnetic yoke 8 is formed in the slider 18, the magnetic probe 6 is positioned so as to be close to the end of the magnetic yoke 8, and the cantilever 5 provided with the magnetic probe 6 at the tip is supported. Member 4
Is adhered to the slider 18 via the. In the figure, 1
Reference numeral 9 denotes a side member constituting a part of the slider 18. Then, the displacement measuring means 7 for observing the displacement of the cantilever 5 may be constituted by an optical system movable together with the slider 18 so that a reproduction signal from the magnetic recording medium 2 may be obtained.

Next, a second embodiment of the present invention will be described. FIG. 7 is a schematic configuration diagram illustrating the magnetic reproducing apparatus according to the present embodiment. In the present embodiment, as shown in FIG. 7, the Z-axis (height direction) provided at the base end of the cantilever 5 and capable of adjusting the distance between the magnetic probe 6 and the magnetic yoke 8 is added to the configuration of the first embodiment. ), And an amplifier 22 for comparing the output Uo from the displacement measuring means 7 with the steady state Us.

In this embodiment, the magnetic yoke 8 is magnetized by the leakage magnetic field from the recording bit recorded on the magnetic recording medium 2, and furthermore, the magnetic probe 6 is magnetized by the magnetic field generated by the magnetic flux from the magnetic yoke 8. When a magnetic interaction force (magnetic force) acts on the magnetic probe 6 and a magnetic force acts on the magnetic probe 6, the cantilever 5 is distorted in accordance with the magnetic force. The displacement of the cantilever 5 distorted in accordance with the magnetic force in this way is measured, and the amplifier 22 compares the change from the steady state with the steady state where no magnetic force is received by the Z-axis (height direction). Is controlled so that the distortion amount of the cantilever 5 becomes zero. It should be noted that the distortion amount of the cantilever 5 may be controlled to be constant. In this case, the feedback control is performed such that the force applied to the magnetic probe 6 is kept constant by controlling the voltage applied to the drive mechanism 21 in the Z axis (height direction). Further, the feedback signal Uz
, The magnetization state recorded on the magnetic recording medium 2 can be detected, and the recorded information can be reproduced.

The Z-axis (height direction) drive mechanism 21
As lead zirconate titanate (Pb (Zr, Ti)
₃ : PZT) A piezo actuator may be used.

Next, a third embodiment of the present invention will be described. FIG. 8 is a schematic configuration diagram showing the magnetic reproducing apparatus according to the present embodiment. In the present embodiment, as shown in FIG.
In the configuration of the embodiment, a phase meter 23 for detecting a phase change of the cantilever 5 and transmitting a signal Uf, and a cantilever vibration means 24 for vibrating the cantilever 5 at a constant frequency near its resonance frequency are added. I have. The cantilever vibrating means 24 is constituted by a laminated piezo actuator. It should be noted that a voltage that gives vibration to the drive mechanism 21 in the Z axis (height direction) is superimposed,
The drive mechanism 21 for the Z axis (height direction) may be configured to also serve as the vibration means 24.

In this embodiment, the recording bits recorded on the magnetic recording medium 2 are reproduced based on the same principle as the so-called "dynamic mode" in the SPM technique. That is, when the gradient of the force acting on the magnetic probe 6 changes, the resonance frequency of the cantilever 5 changes, and the vibration amplitude of the cantilever 5 changes with the change of the resonance frequency, that is, the beat signal which is phase-modulated by the change of the optical path. Is detected, and only the fundamental vibration frequency component of the cantilever 5 is extracted by the lock-in amplifier, thereby obtaining a change in the vibration amplitude or phase of the cantilever 5. Then, the amount of change from the steady state is fed back to the drive mechanism 21 for the Z axis (height direction) to control the detection signal Uf to be constant, and by observing the feedback signal Uz, the magnetic recording medium 2 is controlled. Is detected.

Therefore, according to the present embodiment, as a method for detecting the gradient of the magnetic force, the detection sensitivity can be increased as compared with the method for detecting the magnetic force itself, and the magnetic force to be detected is weak. It is sometimes advantageous. Also,
The detection method according to the present embodiment has an advantage that it is AC-like and is resistant to disturbance such as drift of an optical system at a low frequency.

[0026]

As described above, according to the present invention,
Since the magnetic yoke is arranged between the magnetic recording medium and the magnetic probe, the distance between the magnetic recording medium and the magnetic yoke can be increased even when reproducing information recorded at a high density using the SPM technique. Even if there is some fluctuation, the fluctuation of the magnetic force felt by the magnetic probe is reduced, the recording signal can be reproduced without being affected by the fluctuation of the interval between the recording medium and the probe, and the surface shape of the recording medium is not affected. Thus, the recorded signal can be reproduced. Also, since the magnetic yoke disposed between the magnetic recording medium and the magnetic probe serves as a protective film for the magnetic probe, the magnetic probe does not come into direct contact with the magnetic recording medium. In addition, the risk that the supporting piece for supporting the magnetic recording medium is damaged by collision with the magnetic recording medium is reduced. Further, if the length of the magnetic yoke is set to be equal to or longer than the distance at which the atomic force acts, the magnetic probe can detect only the magnetic force without being affected by the atomic force. Therefore, the influence of the surface shape of the magnetic recording medium on the reproduction signal can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a magnetic reproducing apparatus according to a first embodiment of the present invention.

FIGS. 2A, 2B and 2C are perspective views showing various cantilevers.

FIG. 3 is a block diagram of an optical system showing an example of heterodyne interferometry.

FIG. 4 is a characteristic diagram showing a change in magnetic flux density in a magnetic yoke.

5A is a perspective view of a cantilever provided in a slider, FIG. 5B is a cross-sectional view taken along the line AA in FIG. 5A,
FIG. 5C is a cross-sectional view taken along the line BB in FIG.

FIG. 6 is an enlarged perspective view of a portion C in FIG. 5 (a).

FIG. 7 is a schematic configuration diagram showing a magnetic reproducing apparatus according to a second embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a magnetic reproducing apparatus according to a third embodiment of the present invention.

FIG. 9 is a schematic diagram showing a signal detection method of a scanning probe microscope of a static mode type according to a conventional example.

FIG. 10 is a schematic diagram showing a signal detection method of a scanning probe microscope of a dynamic mode type according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic recording medium 2 Magnetic recording medium 5 Supporting piece (cantilever) 6 Probe 7 Displacement measuring means 8 Magnetic yoke 24 Vibration means

Claims (4)

(57) [Claims] 1. A flexible support piece having a predetermined length and supported at one end in a longitudinal direction, and provided at a support piece at the other end in the longitudinal direction to face a magnetic recording medium. A magnetic probe, a displacement measuring means for detecting a displacement of the support piece in a direction approaching and moving away from the magnetic recording medium, and a thin film magnetic material interposed between the magnetic recording medium and the magnetic probe. And a magnetic yoke. 2. The magnetic reproducing apparatus according to claim 1, wherein the magnetic yoke is supported by a non-magnetic core, and a support piece at one end in the longitudinal direction is supported by the non-magnetic core. 3. The displacement amount of the support piece is controlled to 0 or a constant value according to a value detected by the displacement measuring means.
Or the magnetic reproducing device according to 2. 4. The magnetic reproducing apparatus according to claim 3, further comprising a vibrating means for vibrating the support piece at a constant frequency.