JPH09134551A - Signal reproducing method in magnetic recording and reproducing device and magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the reproduction of high sensitivity and high S/N by applying a DC voltage between a probe and a recording layer to make a tunnel current flow between the tip of the probe and a magnetic recording medium and to detect the change of the tunnel current. SOLUTION: When a DC voltage from a DC voltage source 17 is applied between a probe 15 and a recording layer 13, a tunnel current flows between the probe 15 and the recording layer 13. When the probe 15 and a magnetic recording medium 11 is substantially brought into contact with each other and both of them are relatively moved in the direction of the length of a recording track show by an arrow A, the tunnel current is changed in response to the change of the recording magnetization of the recording layer 13. The change of the tunnel current is detected as the change of a voltage which appears across both terminals of a detection resistor 16, and the voltage change is amplified by an amplifier 18 and extracted as a reproduction signal. Since the line resolution of reproduction is determined by the film thickness of the probe 15, high line resolution is easily obtained. Reproduction line resolution of 400 to 500kFCI can be obtained by making the film thickness not more than 20nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal reproducing method and a magnetic recording / reproducing apparatus in a magnetic recording / reproducing apparatus for realizing high linear recording density and track density.

[0002]

2. Description of the Related Art Generally, in order to further increase the linear recording density in a magnetic recording / reproducing apparatus such as a magnetic disk apparatus, in addition to improving the performance of the magnetic recording medium and reducing the spacing between the head and the medium, The magnetic gap length of the magnetic head, especially the reproducing head, must be reduced.

However, even if the magnetic gap length of the reproducing head is reduced, the throat height of the magnetic gap must be reduced in order to secure the reproduction output. This requires high-precision machining of throat height, which is expected to be difficult with the extension of the current machining technology. Further, as the recording density of the magnetic disk device is improved, contact recording in which a magnetic head is brought into contact with a magnetic recording medium to perform recording is adopted, and the magnetic gap is worn out or disappears in a short time. Is also concerned. Against this background, at least for reproduction, a technique that enables reproduction with an ultra-high linear resolution different from the conventional technique is desired.

[0004]

As described above, the signal reproducing technique of the conventional magnetic recording / reproducing apparatus has a problem that it is difficult to increase the linear resolution during signal reproduction to a level higher than the current level.

The present invention solves such a problem, can significantly improve the linear resolution (linear recording density), has a high sensitivity, a high SN ratio, and can reproduce a signal in a wide frequency band. An object of the present invention is to provide a signal reproducing method in a recording / reproducing apparatus and a magnetic recording / reproducing apparatus.

[0006]

In order to solve the above-mentioned problems, a signal reproducing method according to the first aspect of the present invention is directed to a magnetic recording medium having a conductive recording layer with its tip facing the magnetic recording medium. A probe made of a ferromagnetic film is provided so as to be relatively movable, a DC voltage is applied between the probe and the recording layer, and a tunnel current flows between the two via a non-conductive non-magnetic layer. The signal recorded on the magnetic recording medium is reproduced by causing the current to flow and detecting the change in the tunnel current.

The magnetic recording / reproducing apparatus according to the first aspect of the invention is a magnetic recording for recording / reproducing signals using a magnetic recording medium in which a non-conductive non-magnetic layer is provided on a conductive recording layer. In a reproducing apparatus, a probe composed of a ferromagnetic film is provided so that its tip faces a magnetic recording medium and is movable relative to the magnetic recording medium, and a DC voltage is applied between the probe and the recording layer. Recorded on the magnetic recording medium by detecting the tunnel current flowing from the tip of the probe to the recording layer via the non-magnetic layer by applying the DC voltage by the DC voltage applying unit. And a means for reproducing a signal.

In this way, when a predetermined DC voltage is applied between the probe and the recording layer and a tunnel current is passed between the two through the non-conductive non-magnetic layer, the applied voltage is constant. Below, the tunnel current density changes according to the angle formed by the magnetization of the probe and the magnetization of the recording layer, and the electrical resistance of the non-magnetic layer also changes with this angle change, so the signal recorded on the magnetic recording medium is changed. The tunnel current will change according to the recording magnetization of the recording layer based on. Therefore, the magnetization of the recording layer, that is, the signal recorded on the magnetic recording medium can be reproduced by detecting the change in the tunnel current.

In this case, the area through which the tunnel current flows is substantially equal to the area of the probe facing the magnetic recording medium, and therefore the extremely high reproduction is achieved by reducing the thickness of the probe and the area of the probe facing the medium. Resolution is easily obtained.

In the first invention, when the area of the surface of the probe facing the magnetic recording medium is S, the value of the tunnel current is 1.
It is preferable to select the DC voltage applied to the probe so that it is not less than × 10 ¹¹ × S [A].

When a resistor connected in series with the probe is used for detecting the tunnel current in the first invention, the resistance value of the current detecting resistor is preferably 100Ω or less.

In the signal reproducing method according to the second aspect of the present invention, the tip of the magnetic recording medium having a conductive recording layer is opposed to the magnetic recording medium so that the probe is made of a ferromagnetic film so as to be movable relative to the magnetic recording medium. A signal recorded on the magnetic recording medium is provided by providing a constant tunnel current between the tip of the probe and the magnetic recording medium and detecting a change in voltage generated between the probe and the recording layer. It is characterized by playing.

A magnetic recording / reproducing apparatus according to a second aspect of the present invention is a magnetic recording apparatus for recording and reproducing signals using a magnetic recording medium having a non-conductive non-magnetic layer provided on a conductive recording layer. In the reproducing device, a probe made of a ferromagnetic film is provided so that its tip is opposed to the magnetic recording medium and is movable relative to the magnetic recording medium, and a constant current supply means connected to the probe. A voltage generated between the probe and the recording layer based on a constant tunnel current flowing between the tip of the probe and the recording layer via the nonmagnetic layer by the supply of the constant current from the constant current supply means. Means for reproducing the signal recorded on the magnetic recording medium by detecting the change in

When a constant tunnel current is passed between the probe and the recording layer via the non-conductive non-magnetic layer, the angle between the magnetization of the probe and the magnetization of the recording layer changes. As the electric resistance (or electric conductance) of the non-magnetic layer changes with the change, the voltage generated between the probe and the recording layer changes with the change of the electric resistance. Therefore, the magnetization of the recording layer, that is, the signal recorded on the magnetic recording medium can be reproduced by detecting this voltage change.

In this case as well, the area through which the tunnel current flows is approximately equal to the area of the probe facing the magnetic recording medium, so that the area of the probe facing the medium is made extremely small by reducing the thickness of the probe. High reproduction resolution can be easily obtained.

In the first and second inventions, the thickness of the probe is preferably 50 nm or less, and the thickness of the nonconductive nonmagnetic layer is preferably 10 nm or less.

In the magnetic recording / reproducing apparatus according to the first and second aspects of the invention, the probe is laminated with an antiferromagnetic film or a hard magnetic film for fixing the magnetization of the probe in a predetermined direction. preferable. By doing so, it is possible to prevent the magnetization of the probe from being destabilized by the change of the signal magnetic field that the probe receives from the recording magnetization of the recording layer during signal reproduction, so that the probe is more stable and has a high SN ratio. It becomes possible to reproduce the signal.

Further, in the first and second inventions, it is preferable that the probe is surrounded by a good heat conductive insulating layer except for the surface facing the magnetic recording medium.

When the magnetic recording / reproducing apparatus according to the first and second aspects of the present invention is configured as a fixed magnetic disk device, a recording element for recording a signal on a rotating disk-shaped magnetic recording medium and a magnetic recording medium are recorded. A head element is constituted by a reproducing element including at least a probe for reproducing a signal, and the head portion is mounted on the head slider. Here, the head slider has a slider portion having a slider surface facing the magnetic recording medium so that a fluid force generated by a dynamic pressure effect of a gas flow such as air accompanying the rotation of the magnetic recording medium acts, and the slider portion. Head support that is connected to the magnetic recording medium, supports the head portion so that its tip contacts the magnetic recording medium, has a smaller mass than the slider portion, and has an area of the surface facing the magnetic recording medium smaller than the area of the slider surface. And part.

According to the fixed magnetic disk device having such a structure, the head portion composed of the reproducing element and the recording element having the probe as the main element can be stably and reliably brought into contact with the magnetic recording medium. As a result, fluctuations in the tunnel current flowing from the probe to the magnetic disk due to spacing fluctuations during signal reproduction become extremely small, and stable signal reproduction with a high SN ratio becomes possible.

In the magnetic recording / reproducing apparatus according to the first aspect of the present invention, further, current detecting means for detecting a tunnel current,
A low-pass filter that receives the output signal from the current detecting means, and a DC voltage applied between the probe and the recording layer by the DC voltage applying means based on the difference between the output signal of the low-pass filter and the target signal. It is preferable to have a control means for controlling This makes it possible to prevent changes in tunnel current due to surface waviness and surface irregularities of the recording medium, and more stable signal reproduction becomes possible.

In the magnetic recording / reproducing apparatus according to the first and second aspects of the invention, the shape of the probe is made substantially equal to the reproducing track width in the vicinity of the medium facing surface, and is wider than the reproducing track width in the inner part of the head. Is preferred. By doing this, in addition to reducing the electrical resistance value of the entire probe,
Since the density of the current flowing through the probe is lower in the back of the head than in the vicinity of the medium facing surface, it is possible to suppress the heat generation of the entire probe, allowing a larger tunneling current to flow and thus a larger reproduction. A signal output can be obtained.

In the signal reproducing method according to the third aspect of the invention, a probe made of a ferromagnetic film is arranged so that the tip is opposed to a magnetic recording medium having a conductive recording layer and is movable relative to the magnetic recording medium. A high-frequency voltage is applied between the probe and the recording layer to cause a high-frequency tunnel current to flow between the tip of the probe and the magnetic recording medium, thereby recording on the recording layer directly below the probe. A signal recorded in a magnetic recording medium is reproduced by causing a ferromagnetic resonance in the magnetization and detecting a high frequency magnetic flux generated from the recording magnetization due to the ferromagnetic resonance.

The magnetic recording / reproducing apparatus according to the third aspect of the invention is a magnetic recording system for recording and reproducing signals using a magnetic recording medium having a non-conductive non-magnetic layer on a conductive recording layer. In a reproducing apparatus, a probe formed of a ferromagnetic film is provided so that its tip is opposed to the magnetic recording medium and is movable relative to the magnetic recording medium, and the probe is provided between the probe and the recording layer. High-frequency voltage applying means for applying a high-frequency voltage having a frequency at which the magnetization in the recording layer immediately below causes ferromagnetic resonance, and provided in the vicinity of the probe so as to be movable relative to the magnetic recording medium together with the probe, By detecting the change of the high-frequency magnetic flux generated from the recording magnetization of the recording layer based on the high-frequency tunnel current flowing from the tip of the probe to the recording layer via the non-magnetic layer by applying the high-frequency voltage by the high-frequency voltage applying means. , The high-frequency magnet A detection coil that outputs a detection signal corresponding to the change in the magnetic field and a detection unit that detects the detection signal output from the detection coil to obtain a reproduction signal corresponding to the signal recorded on the magnetic recording medium. Is characterized by. The probe and the detection coil are preferably arranged so as to be electromagnetically orthogonal to each other in order to prevent mutual coupling and to obtain a high quality reproduction signal.

When a predetermined high-frequency voltage is applied between the probe and the recording layer in this way, and a high-frequency tunnel current is caused to flow between them through the non-conductive non-magnetic layer, this tunnel A high-frequency magnetic field is generated by the current and applied to the recording magnetization of the recording layer directly below the probe. Here, when the frequency of the high frequency voltage is set so that the recording magnetization causes the ferromagnetic resonance and the probe is moved relative to the magnetic recording medium, the ferromagnetic resonance condition changes according to the change of the recording magnetization. To do. When ferromagnetic resonance occurs, the recording magnetization precesses in the recording layer,
Express high frequency magnetization. The high frequency magnetic flux generated from the high frequency magnetization generated by the recording magnetization is detected by the detection coil arranged near the probe, and high frequency induced electromotive force is generated at both ends of the detection coil. Since this induced electromotive force, that is, the output signal of the detection coil is modulated by the change in the recording magnetization, it is possible to reproduce the signal recorded on the magnetic recording medium by detecting this.

In the signal reproducing method according to the fourth aspect of the present invention, a probe made of a ferromagnetic film is arranged so that its tip is opposed to a magnetic recording medium having a conductive recording layer and is movable relative to the magnetic recording medium. By providing a constant high-frequency tunnel current between the tip of the probe and the magnetic recording medium, ferromagnetic resonance is caused in the recording magnetization of the recording layer immediately below the probe, and this ferromagnetic resonance The signal recorded on the magnetic recording medium is reproduced by detecting a high frequency magnetic flux generated from the recording magnetization due to the magnetic field.

In the magnetic recording / reproducing apparatus according to the fourth aspect of the invention, a magnetic recording medium for recording and reproducing signals using a magnetic recording medium in which a non-conductive non-magnetic layer is provided on a conductive recording layer. In a reproducing device, a probe formed of a ferromagnetic film is provided so as to be movable relative to the magnetic recording medium with its tip facing the magnetic recording medium, and a probe connected to the probe and directly below the probe. A high frequency constant current supply means for supplying a high frequency constant current of a frequency at which the magnetization in the recording layer causes ferromagnetic resonance;
The probe is provided in the vicinity of the probe so as to be movable relative to the magnetic recording medium together with the probe. A detection coil that outputs a detection signal corresponding to the change in the high frequency magnetic flux by detecting the change in the high frequency magnetic flux generated from the recording magnetization of the recording layer based on a constant tunnel current, and the detection output from this detection coil. And a detection means for detecting a signal to obtain a reproduction signal corresponding to the signal recorded on the magnetic recording medium.

In this way, when a high frequency constant current is supplied via the probe and a high frequency tunnel current is caused to flow between the two via a non-conductive nonmagnetic layer, the high frequency magnetic field is generated by the tunnel current. Is generated and applied to the recording magnetization of the recording layer immediately below the probe. Here, when the frequency of a constant current of high frequency is set so that the recording magnetization causes ferromagnetic resonance and the probe is moved relative to the magnetic recording medium, the ferromagnetic resonance condition is changed according to the change of the recording magnetization. Changes. When the ferromagnetic resonance occurs, the recording magnetization precesses in the recording layer and expresses high frequency magnetization. The high frequency magnetic flux generated from the high frequency magnetization generated by the recording magnetization is detected by the detection coil arranged near the probe, and high frequency induced electromotive force is generated at both ends of the detection coil. Since this induced electromotive force, that is, the output signal of the detection coil is modulated by the change in the recording magnetization, it is possible to reproduce the signal recorded on the magnetic recording medium by detecting this.

In the third and fourth aspects of the invention, since the area through which the high-frequency tunnel current flows is approximately equal to the area of the probe facing the magnetic recording medium, the thickness of the probe is made small and the area of the probe facing the medium is reduced. By reducing, it is possible to easily obtain extremely high reproduction resolution.

Further, since the ferromagnetic resonance frequency of the recording magnetization is as high as several gigahertz to 20 gigahertz, even if the magnitude of the high frequency magnetic flux itself is small, a large induced electromotive force is generated in proportion to the magnitude of the frequency. Therefore, a sufficiently large reproduced signal output can be obtained.

In the magnetic recording / reproducing apparatus according to the third and fourth inventions, the probe is composed of at least two conductive films arranged along the relative movement direction with respect to the magnetic recording medium, and these conductive films are formed. There is a predetermined distance in the relative movement direction in the vicinity of the surface facing the magnetic recording medium, and the other portions are electrically connected to each other, and the detection coil is electrically connected to the two conductive sheets near the surface facing the magnetic recording medium. It is preferably arranged between the permeable membranes.

By doing so, the recording magnetization of the recording layer located immediately below the detection coil is stronger and has a higher linear resolution due to the high-frequency tunnel currents of the two paths that flow directly below each of the two conductive films forming the probe. Since a sharp high-frequency magnetic field can be applied depending on the direction, signal reproduction with higher sensitivity and higher line resolution becomes possible.

When the magnetic recording / reproducing apparatus according to the third and fourth aspects of the present invention is configured as a fixed magnetic disk device, a recording element for recording a signal on the rotating disk-shaped magnetic recording medium and the magnetic recording medium are recorded. A head portion is composed of a probe for reproducing a signal and a reproducing element including at least a detection coil, and the head portion is mounted on a head slider. Also in this case, the head slider is provided with a slider surface facing the magnetic recording medium so that the fluid force generated by the dynamic pressure effect of the flow of gas such as air accompanying the rotation of the magnetic recording medium acts on the head slider. Section and the slider section, which supports the head section so that its tip contacts the magnetic recording medium, has a smaller mass than the slider section, and the area of the surface facing the magnetic recording medium is the area of the slider surface. And a head support portion smaller than the head support portion, it is possible to stably and reliably make the head portion composed of a reproducing element and a recording element having a probe and a detection coil as main elements travel in contact with the magnetic recording medium. As a result, fluctuations in high-frequency tunnel current flowing from the probe to the magnetic disk due to spacing fluctuations during signal reproduction are extremely small. , It is possible to signal reproduction of stable and highly SN ratio.

In the magnetic recording / reproducing apparatus according to the third aspect of the present invention, a current detecting means for detecting a high frequency tunnel current, a detecting circuit for detecting an output signal from the current detecting means, and an output signal of the detecting circuit. And a control means for controlling the high-frequency voltage applied between the probe and the recording layer by the high-frequency voltage applying means based on the difference between the output signal of the low-pass filter and the target signal. Is preferred. By doing so, it is possible to prevent changes in the high-frequency tunnel current due to the surface waviness and surface irregularities of the magnetic recording medium, and more stable signal reproduction becomes possible.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first signal reproducing method according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, a very thin (about 10 nm) non-conductive non-magnetic layer 2 is provided on a recording layer 3 to form a magnetic recording medium, and a conductive layer is formed on the magnetic recording medium. The probe 1 made of a ferromagnetic film is arranged so that the tips thereof face each other so as to be in contact with or substantially in contact with each other, and when a predetermined DC voltage V is applied between the probe 1 and the recording layer 3, A tunnel current flows between the recording layer 3 and the recording layer 3 via the nonmagnetic layer 2. The non-conductive non-magnetic layer 2 may be an insulator or a semiconductor layer. There is a relationship as shown in FIG. 2 between the tunnel current density Jt and the applied voltage V.

Here, when the applied voltage V is constant, the tunnel current density Jt changes according to the angle θ formed by the magnetization of the probe 1 and the magnetization of the recording layer 3. Therefore, when the angle θ changes, the electric resistance Rt of the nonmagnetic layer 2 is changed as shown in FIG.
(Or the electric conductance Gt which is the reciprocal thereof) also changes. Such a phenomenon is called a magnetic tunnel effect. Generally, this electrical resistance Rt is
And the magnetization of the recording layer 3 are parallel (θ = 0 ° or 360
It is known that the angle becomes minimum at (°) and becomes maximum at antiparallel (θ = 180 °).

Therefore, when the probe 1 is moved relative to the magnetic recording medium while the probe 1 is in contact with the magnetic recording medium having the recording magnetization formed on the recording layer 3, as shown in FIG. The tunnel current density Jt changes according to the recording magnetization of No. 3. Therefore, the change ΔJ of this tunnel current density Jt
By detecting t, the magnetization of the recording layer 3, that is, the signal recorded on the magnetic recording medium can be reproduced.

The above is the principle of the first signal reproducing method according to the present invention. In this case, the area where the tunnel current flows is approximately equal to the area where the probe 1 faces the magnetic recording medium. Therefore, by reducing the thickness of the probe 1 to reduce the medium facing area of the probe 1, a high reproduction resolution can be easily obtained.

Next, an embodiment of the magnetic recording / reproducing apparatus based on the above-mentioned first signal reproducing method according to the present invention will be described.

<First Embodiment> FIG. 5 is a view showing the schematic arrangement of a magnetic recording / reproducing apparatus according to the first embodiment.
The magnetic recording medium 11 has a structure in which a soft magnetic layer 14, a perpendicular recording layer 13, and a nonmagnetic layer 12 are sequentially stacked on a medium substrate (not shown). On this magnetic recording medium 11,
The tip of the probe 15 made of a conductive ferromagnetic film is in contact. The easy axis of magnetization of the probe 15 is set in its longitudinal direction,
It is oriented in a direction perpendicular to the surface of the magnetic recording medium 11. At least one of the perpendicular recording layer 13 and the soft magnetic layer 14 is electrically grounded, and the probe 15 is grounded via a current detection resistor 16 and a DC voltage source 17 in series. An amplifier 18 is connected to both ends of the current detection resistor 16.

In such a configuration, the DC voltage source 17
When a DC voltage is applied between the probe 15 and the perpendicular recording layer 13, a tunnel current flows between the probe 15 and the perpendicular recording layer 13. When the probe 15 and the magnetic recording medium 11 are substantially brought into contact with each other and both are relatively moved in the recording track longitudinal direction indicated by the arrow A, the tunnel current changes in accordance with the change in the recording magnetization of the perpendicular recording layer 13. This change in tunnel current is detected as a voltage change appearing across the detection resistor 16, and this voltage change is amplified by the amplifier 18 and taken out as a reproduction signal.

Here, as the non-conductive non-magnetic layer 12, a film of Al ₂ O ₃ , Si ₃ N ₄ , C (diamond) or the like can be used as long as it is an insulating material, and as a semiconductor material. A Ge-based film, a Si-based film, or the like can be used. As the perpendicular recording layer 13, CoCr-based, CoPt-based,
Fe as the SmCo-based ferromagnetic film and the soft magnetic layer 14
Ferromagnetic films of Co type and Co type can be used respectively. As the probe 15, Fe or Fe-based or Co
A ferromagnetic film such as a system can be used.

According to this embodiment, since the linear resolution of reproduction is determined by the film thickness t of the probe 15, a high linear resolution can be easily obtained. For example, if the recording is performed at a sufficiently high density, a reproduction line resolution of 400 to 500 kFCI can be obtained by setting the film thickness t to 50 nm or less, preferably 20 nm or less. The value of this reproduction line resolution corresponds to 5 to 10 times the value obtained in the prior art.

Further, since the probe 15 has an extremely thin film thickness and a simple structure, the processing is easy and the processing accuracy can be high. Therefore, it is extremely easy to narrow the track of the probe 15 to a submicron order or less.
It is possible to increase the manufacturing yield of the reproducing element including 5 as a main element.

Further, the distance between the probe 15 and the perpendicular recording layer 13 is set to 10 nm or less, and the value of the detection resistor 16 is set to 100 Ω or less so that the tunnel current density is 1 × 10.
¹¹ [A / m ² ] When the voltage applied to the surface of the probe 15 facing the magnetic recording medium 11 is adjusted to be ¹¹ [A / m ² ] or more, signal reproduction is performed with extremely high sensitivity, high SN ratio, and high signal frequency band. It can be carried out. Therefore, the areal recording density of the magnetic recording device can be dramatically improved as compared with the conventional technique.

In the present embodiment, the magnetization of the probe 15 is provided with sufficient anisotropy so as not to be moved by the signal magnetic field received from the magnetic recording medium 11 in order to avoid unstable operation of the reproduction signal output. It is desirable to take measures such as keeping.

Further, although the vertical recording method has been described in the present embodiment, the present invention can be applied to the longitudinal recording method and the lateral recording method.

<Second Embodiment> FIG. 6 is a view showing the arrangement of the essential parts of a magnetic recording / reproducing apparatus according to the second embodiment.
FeMn, Ni is added to the probe 15 made of a conductive ferromagnetic film.
Antiferromagnetic film 20 or CoP made of O, PtMn, etc.
This is an example in which a hard magnetic film made of a t-based or CoCr-based material is laminated and the magnetization of the probe 15 is fixed in a predetermined direction, and the other points are the same as in the first embodiment. Reference numeral 21 denotes a surface of the head portion facing the magnetic recording medium (medium facing surface).

According to this embodiment, the probe 1 is used during signal reproduction.
It is possible to prevent the magnetization of the probe 15 from being destabilized by the change in the signal magnetic field which the magnetic field 5 receives from the recording magnetization of the recording layer 13. Therefore, it is possible to reproduce signals with high stability and a high SN ratio. In the case of the perpendicular recording method in this embodiment, it is desirable that the magnetization of the probe 15 be oriented in the direction perpendicular to the surface of the magnetic recording medium, but it may be fixed in any direction depending on the recording method.

<Third Embodiment> FIG. 7 is a view showing a main configuration of a magnetic recording / reproducing apparatus according to the third embodiment.
(A) is a cross-sectional view in the direction of relative movement of the head and the medium, and (b) is a cross-sectional view of the reproducing element seen from the surface side of the magnetic recording medium.
In the present embodiment, the non-magnetic insulating layer 19 having high thermal conductivity such as Al ₂ O ₃ , Si ₃ N ₄ , C (diamond or diamond-like) is provided around the probe 15 except for the surface facing the magnetic recording medium. It has a structure surrounded by -1, 19-2, and is otherwise similar to the first embodiment. By doing so, a larger tunnel current can be made to flow, so that the signal reproduction output can be made higher.

It should be noted that the probe 15 may be formed by laminating the antiferromagnetic film or the hard magnetic film described in the first embodiment with a nonmagnetic insulating layer.

<Fourth Embodiment> FIG. 8 is a cross-sectional view in the head / medium relative movement direction showing a main part configuration of a magnetic recording / reproducing apparatus according to a fourth embodiment. Is.

That is, the magnetic recording medium 11 has a recording layer 13 in which recording magnetization is formed in the lateral direction (recording track width direction).
The magnetic recording medium 1 has a structure in which a non-magnetic layer 12 is laminated on the magnetic recording medium 11. A probe 15 having an easy axis of magnetization in the recording track width direction is brought into contact with the magnetic recording medium 11, and the probe 15 is attached to the magnetic recording medium 1.
The signal is reproduced by moving it in the direction of arrow A relative to 1. Even in such a lateral recording method, the same effect as that of the above embodiment can be obtained.

<Fifth Embodiment> Next, a fifth embodiment in which the present invention is applied to a fixed magnetic disk device will be described with reference to FIGS.

As shown in FIG. 9, in the fixed magnetic disk device of this embodiment, a disk-shaped magnetic recording medium (magnetic disk) 101 is rotationally driven by a spindle motor 102. A head portion including a recording element for recording / reproducing a signal on the magnetic disk 101 and a reproducing element including the probe described in the above embodiment is mounted on a head slider 103, and the head slider 103 is provided with a suspension 104. It is supported by the arm 105. The arm 105 is supported by the fixed shaft 107, and is swung in the radial direction of the magnetic disk 101 by the voice coil motor 106, so that the head portion is moved to the magnetic disk 1.
01 is controlled to be located on the target track.

FIG. 10 is an enlarged perspective view showing the structure around the head slider 103. Head slider 103
Is a slider portion 110 having a slider surface 109 facing the magnetic disk 101 so that a fluid force generated by a dynamic pressure effect of a gas flow such as air accompanying the rotation of the magnetic disk 101 acts on the slider portion 110. It comprises a rod-shaped head support 111 connected to each other. Head support 111
Is a contact portion 112 formed of a ridge formed on the surface facing the magnetic disk 101, a base end portion 113 connected to the slider portion 110, and a head forming surface 114 located on the end surface opposite to the slider portion 111. Have. Head forming surface 11
4, a surface 21 facing the magnetic disk 101 has a contact portion 1
A head portion is formed so as to be in contact with the magnetic disk 101 and located on substantially the same plane as the surface of the magnetic disk 101 facing the magnetic disk 101.

Here, the head support portion 111 has a smaller mass than the slider portion 110, and the area of the surface of the contact portion 112 facing the magnetic disk 101 is smaller than the area of the slider surface 109. .

FIG. 11 is a diagram showing a specific structure of the recording element and the reproducing element which constitute the head portion mounted on the head slider 103. As shown in the figure, the head forming surface 114 of the head supporting portion 111 of the slider portion 110.
A reproducing element including the probe 15 and a recording element including a ring-type thin film magnetic head are laminated on the upper portion by a thin film process. FIG. 11A shows the probe 15 and the non-magnetic insulating layer 201 on the head forming surface 114 of the head supporting portion 111.
A reproducing element 200 composed of
On top of this, a ring-shaped magnetic core 204 and recording coil 20
5 is an example in which a recording element 203 including 5 and a non-magnetic insulating layer 206 that covers them is laminated. FIG. 11 (b) is shown in FIG.
Contrary to 1 (a), the head forming surface 1 of the head supporting portion 111
In this example, the recording element 203 and the reproducing element 200 are sequentially stacked on the recording layer 14.

According to this embodiment, the reproducing element 200 and the recording element 203 having the probe 15 as a main element can be stably and reliably contact-traveled with respect to the magnetic disk 101. Therefore, during signal reproduction, fluctuations in the tunnel current flowing between the probe 15 and the magnetic disk 101 due to spacing fluctuations become extremely small, and stable signal reproduction with a high SN ratio becomes possible.

When the perpendicular magnetization recording medium is used, a single magnetic pole type recording element may be used as the recording element.

<Sixth Embodiment> FIG. 12 is a perspective view showing a structure of a main part of a magnetic recording / reproducing apparatus according to a sixth embodiment, in which the shape of the probe 15 is narrow near the medium facing surface 21. Then, this width is set as a reproduction track width, which is wider than the reproduction track width in the inner part of the head, and the thin-film lead wire 115 of good conductor is laminated on the probe 15 in the inner part of the head. The thin film lead wire 115 is provided on the head forming surface 11 of the head supporting portion 111.
4 is in contact with the probe 15 and extends from the head forming surface 114 to the surface opposite to the contact portion 112.
The end portion on the side opposite to the probe 15 is connected to the current detecting resistor 16 shown in FIG. In FIG. 12, the recording element and its lead wire are omitted.

According to this embodiment, since the probe 15 has the above-described shape, the electric resistance value of the probe 15 as a whole is reduced and the density of the current flowing through the probe 15 is a medium. Since the head inner part is smaller than the vicinity of the facing surface 21, it is possible to suppress heat generation of the entire probe 15. As a result, a larger tunnel current can flow,
There is an advantage that a larger reproduction signal output can be obtained.

<Seventh Embodiment> FIG. 13 is a block diagram of a magnetic recording / reproducing apparatus according to the seventh embodiment. In the present embodiment, the tunnel current is prevented from changing according to the surface waviness and surface irregularities of the magnetic recording medium 11.

In this embodiment, a constant voltage source 31 capable of voltage control is used as the DC voltage source. The voltage across the current detecting resistor 16 is amplified by the amplifier 18 and then input to the low-pass filter 32. The output signal of the low-pass filter 32 has a difference (error) from the target signal, which is the voltage value appearing across the current detection resistor 16 when a predetermined target tunnel current flows, and this error is PI.
It is input to the D controller (proportional-integral-derivative controller) 33. The tunnel current is held constant by controlling the DC voltage output from the constant voltage source 21 by the output signal of the PID controller 33.

When the magnetic recording medium 11 has a surface waviness or surface irregularities, the tunnel current changes greatly.
Significant fluctuations occur in the reproduced signal. However, the cycle of these surface waviness and surface irregularities can be considered to be sufficiently larger than the substantial maximum cycle of the signal recorded on the magnetic recording medium 11, and the amplitude fluctuations of the waviness and irregularities ( In the range in which Δy) does not significantly affect the degree of modulation of the tunnel current due to the magnetic tunnel phenomenon,
The configuration of the present embodiment enables extremely stable high-sensitivity signal reproduction.

Next, the second signal reproducing method according to the present invention will be described with reference to FIG.

As shown in FIG. 14A, as in the first embodiment, a very thin (about 10 nm) non-conductive non-magnetic layer 12 is provided on the recording layer 13 to form the magnetic recording medium 11.
The probe 15 made of a conductive ferromagnetic film is arranged on the magnetic recording medium 11 with the tips facing each other so as to make contact or substantially contact. Here, the probe 15 and the recording layer 13
When a predetermined high frequency voltage Vrf is applied between the probe 15 and
A high-frequency tunnel current flows between the recording layer 13 and the recording layer 13 via the nonmagnetic layer 12. The non-conductive non-magnetic layer 12
May be an insulator or a semiconductor layer.

The tunnel current thus flowing generates a high frequency magnetic field Hrf as shown in FIG. 14B, and this high frequency magnetic field Hrf is applied to the recording magnetization 44 of the recording layer 13 immediately below the probe 15. Here, the frequency f of the high frequency voltage Vrf
Is set so that the recording magnetization 44 causes ferromagnetic resonance, and the probe 15 is moved relative to the magnetic recording medium 11 in the longitudinal direction of the recording track, the ferromagnetic resonance condition is changed according to the change of the recording magnetization 44. Changes. When ferromagnetic resonance occurs,
The recording magnetization 44 performs a precession movement as indicated by a symbol M in the recording layer 13 of FIG. 14C to express high frequency magnetization.

Therefore, the detection coil 41 is provided near the probe 15.
, The recording magnetization 44 is set as shown in FIG.
The high-frequency magnetic flux φrf generated by the high-frequency magnetization generated thereby is linked to the detection coil, and high-frequency induced electromotive force is generated at both ends of the detection coil 41. Since this induced electromotive force is modulated by the change in the recording magnetization 44, this induced electromotive force, that is, the output signal of the detection coil 41 is amplified, and the amplified signal is detected (for example, peak detection) to thereby detect the magnetic recording medium. The signal recorded in 11 can be reproduced.

The above is the principle of the signal reproducing method according to the third invention. Generally, the ferromagnetic resonance frequency of the recording magnetization 44 is as high as several gigahertz to 20 gigahertz. Therefore, according to this signal reproducing method, even if the size of the high frequency magnetic flux φrf itself is small, a large induced electromotive force is generated in proportion to the size of the frequency, so that a sufficiently large reproduced signal output can be obtained.

Ferromagnetic resonance occurs only in the recording magnetization 44 located directly below the probe 15. Since the signal reproduction is performed by detecting the induced electromotive force caused by the ferromagnetic resonance, the linear resolution at the time of reproduction is almost determined by the thickness of the probe 15 in the longitudinal direction of the recording track. This means that extremely large linear resolution (linear recording density) can be obtained.

Next, an embodiment of the magnetic recording / reproducing apparatus based on the above-mentioned second signal reproducing method will be described.

<Eighth Embodiment> FIG. 15 is a view showing the schematic arrangement of a magnetic recording / reproducing apparatus according to the eighth embodiment. A magnetic recording medium 11 is a recording layer 13 on a medium substrate 10.
The non-magnetic layer 12 is sequentially laminated. A conductive probe 15 is in contact with the magnetic recording medium 11. The recording layer 13 is electrically grounded, and the probe 1
5 is grounded via a high frequency voltage source (high frequency oscillator) 42.

On the other hand, a detection coil 41 made of a conductive film is arranged near the probe 15. An amplifier 45 is connected to both ends of the detection coil 41.
The output signal of is input to the detection circuit 46. Also in this embodiment, the same materials as those in the first embodiment can be selected as the materials for the non-magnetic layer 12, the recording layer 13, the probe 15, and the like.

In such a configuration, the high frequency voltage source 4
When a high frequency voltage from 2 is applied between the probe 15 and the recording layer 13, a high frequency tunnel current flows between the probe 15 and the recording layer 13 via the non-magnetic layer 12. Here, probe 1
5 and the magnetic recording medium 11 are brought into substantially contact with each other, and both are indicated by an arrow A.
When relatively moved in the longitudinal direction of the recording track indicated by,
A high-frequency magnetic field Hrf is generated by the high-frequency tunnel current Irf flowing just below the probe 15 in response to a change in the recording magnetization 44 of the recording layer 13, and this high-frequency magnetic field Hrf is recorded to the recording magnetization 44 of the recording layer 13 located directly below the probe 15. Applied to.

As a result, the recording magnetization 44 causes ferromagnetic resonance. When ferromagnetic resonance occurs, the recording magnetization 44 causes a precession movement, and this precession movement causes high frequency magnetization.
Therefore, when the detection coil 41 made of a conductive film is arranged close to the probe 15, the high frequency magnetic flux φrf generated by the high frequency magnetization interlinks with the detection coil 41, so that a high frequency induced electromotive force is generated in the detection coil 41. Occurs.

If the frequency of the high frequency voltage is fixed so that the ferromagnetic resonance occurs in the region where the magnetization is uniformly recorded in the recording layer 13 and the ferromagnetic resonance does not occur in the magnetization reversal region, the magnetic recording medium 11 is recorded. The recording magnetization 44 directly below the probe 15 changes due to the relative movement between the probe 15 and the probe 15, and the induced electromotive force generated in the detection coil 41 changes. The change of the induced electromotive force, that is, the output signal of the detection coil 41 is determined by the amplifier 4
If the signal is detected by the detection circuit 46 after being amplified by 5, the recorded signal can be reproduced with high sensitivity. Detection circuit 46
May have basically any configuration such as a peak detection method.

Also in this embodiment, the same effect as that of the first embodiment can be obtained. In addition to this, in this embodiment, the probe 15 and the detection coil 41 are arranged so as to be electromagnetically orthogonal to each other, and a high-frequency magnetic field based on a high-frequency current (equal to a high-frequency tunnel current) flowing through the probe 15 is generated. Since the detection coil 41 can be prevented from interlinking with the detection coil 41, the detection coil 41 can detect only the high-frequency magnetic flux change corresponding to the change in the recording magnetization, which is advantageous in that high-sensitivity and high-quality signal reproduction can be performed. .

Although the longitudinal recording method has been described in this embodiment, the present invention can be applied to the vertical recording method and the horizontal recording method.

<Ninth Embodiment> In this embodiment, as in the third embodiment described with reference to FIG.
It is surrounded by a nonmagnetic insulating layer having a high thermal conductivity such as l ₂ O ₃ , Si ₃ N ₄ , C (diamond or diamond-like). As a result, a larger high-frequency tunnel current can be passed, and the signal reproduction output can be further increased.

<Tenth Embodiment> FIG. 16 is a view showing the arrangement of a magnetic recording / reproducing apparatus according to the tenth embodiment. As shown in the figure, the probe 15 has a medium facing surface 21.
In the vicinity, it is composed of two conductive films 15-1 and 15-2 arranged in parallel at a predetermined interval along the head / medium moving direction (recording track longitudinal direction) indicated by arrow A, and in the vicinity of the medium facing surface 21. In the head inner portion 47, the conductive films 15-1 and 15-2 are electrically connected to each other. The detection coil 41 is disposed between the two conductive films 15-1 and 15-2 near the medium facing surface 21 while being electrically insulated from the probe 15 by the insulating material 48. The other configurations are the same as those of the eighth embodiment.

According to the present embodiment, in addition to the effect of the eighth embodiment, two conductive films 15-1, 1 forming the probe 15 are provided before and after the detection coil 41 in the longitudinal direction of the recording track.
Since 5-2 is provided, these conductive films 15-2,
Due to the high-frequency tunnel currents of the two paths flowing directly under each of 15-2, the recording magnetization 44 of the recording layer 13 located directly under the detection coil 41 is stronger than in the case of the eighth embodiment, and depending on the line resolution direction. It is possible to apply a sharp high-frequency magnetic field and enable signal reproduction with higher sensitivity and higher line resolution.

<Eleventh Embodiment> This embodiment is shown in FIG.
~ This is an example applied to a fixed magnetic disk device similar to the fifth embodiment described in Fig. 11. The overall configuration of the fixed magnetic disk device in this embodiment is the same as that in FIG. 9, and the configuration of the head slider 103 in FIG. 9 is also the same as that in FIG.

FIG. 17 is a perspective view showing the structure of the reproducing element on the head supporting portion 111 in this embodiment. On the head formation surface 114 of the head support portion 111, the probe 15 made of a conductive film, the detection coil 41 electrically insulated from the probe 15 and arranged electromagnetically orthogonally, the probe 15
Thin-film lead wire 115 connected to and the detection coil 4
A pair of thin film lead wires 116-1 connected to both ends of
116-2 is formed by a thin film process. The thin film lead wires 115 and 116-1, 116-2 are in contact with both ends of the probe 15 and the detection coil 41 on the head forming surface 114 of the head supporting portion 111, and the head forming surface 11
4 is formed to extend on the surface opposite to the contact portion 112, and the end portion of the thin film lead wire 115 opposite to the probe 15 is connected to the high frequency voltage source 42 shown in FIG. The ends of the thin film lead wires 116-1 and 116-2 opposite to the detection coil 41 are connected to the amplifier 45 shown in FIG. In FIG. 17, the recording element and its lead wire are omitted.

FIG. 18 is a diagram showing a specific structure of the recording element and the reproducing element which constitute the head portion mounted on the head slider 103 in this embodiment. As shown in the figure, the probe 15 and the nonmagnetic insulating layer 201 are formed on the head forming surface 114 of the head supporting portion 111 of the slider portion 110.
A reproducing element composed of the detection coil 41 and a recording element composed of a ring-type thin film magnetic head, which are stacked between the probe 15 and the nonmagnetic insulating layer 201 with a thin nonmagnetic insulating layer 202 interposed therebetween, are stacked by a thin film process. It is configured.

In FIG. 18A, a reproducing element 200 composed of the probe 15, the detection coil 41, and the nonmagnetic insulating layers 201 and 202 is formed on the head forming surface 114 of the head supporting portion 111. This is an example in which a recording element 203 including a ring-shaped magnetic core 204, a recording coil 205, and a nonmagnetic insulating layer 206 that covers them is laminated on top. 18B is an example in which the recording element 203 and the reproducing element 200 are sequentially stacked on the head forming surface 114 of the head supporting portion 111, contrary to FIG. 18A.

FIG. 17 is a perspective view showing the structure of the reproducing element on the head supporting portion 111 in more detail. On the head forming surface 114 of the head supporting portion 111, the probe 15 made of a conductive film, and the detection coil 41 electrically insulated from the probe 15 and orthogonally arranged electromagnetically, were connected to the probe 15. A thin film lead wire 115 and a pair of thin film lead wires 116-1 and 116-2 connected to both ends of the detection coil 41 are formed by a thin film process.

Thin film lead wires 115 and 116-1,1
16-2 is a head forming surface 114 of the head supporting portion 111.
The probe 15 of the thin film lead wire 115 is formed so as to contact both ends of the probe 15 and the detection coil 41 and extend from the head forming surface 114 to the surface opposite to the contact portion 112.
15 is connected to the high frequency voltage source 42 shown in FIG. 15, and the ends of the thin film lead wires 116-1 and 116-2 opposite to the detection coil 41 are the amplifier 4 shown in FIG.
5 is connected. In FIG. 17, the recording element and its lead wire are omitted.

Also in this embodiment, the head slider 1
Reference numeral 03 denotes a slider portion 110 having a slider surface 109 facing the magnetic disk 101 so that a fluid force generated by a dynamic pressure effect of a flow of air or the like accompanying the rotation of the magnetic disk 101 acts as shown in FIG. , This slider part 1
10 is a rod-shaped head support 111, and the head support 111 includes a contact portion 112 formed of a ridge formed on a surface facing the magnetic disk 101, and a slider portion 11.
It has a base end portion 113 connected to 0 and a head forming surface 114 located on the end face opposite to the slider portion 111. Further, a head portion is formed on the head forming surface 114 such that the facing surface 21 facing the magnetic disk 101 is located on substantially the same plane as the facing surface of the contact portion 112 facing the magnetic disk 101 and contacts the magnetic disk 101. It The head supporting portion 111 has a smaller mass than the slider portion 110, and the area of the surface of the contact portion 112 facing the magnetic disk 101 is smaller than the area of the slider surface 109.

With this structure, according to the present embodiment, the reproducing element 200 and the recording element 203, which have the probe 15 and the detecting coil 41 as main elements, travel stably and reliably in contact with the magnetic disk 101. It becomes possible. Therefore, at the time of signal reproduction, the fluctuation of the high frequency tunnel current flowing from the probe 15 to the magnetic disk 101 due to the spacing fluctuation becomes extremely small, so that the stable signal reproduction with a high SN ratio becomes possible.

When the perpendicular magnetization recording medium is used, a single pole type recording element may be used as the recording element.

<Twelfth Embodiment> This embodiment is shown in FIG.
Similarly to the sixth embodiment described in 2, the shape of the probe 15 is narrowed in the vicinity of the medium facing surface 21, and this width is set as the reproduction track width, and at the back of the head, it is made wider than the reproduction track width. A thin film lead wire of good conductor is laminated on the probe 15 at the back of the head.

The effect of this embodiment is similar to that of the sixth embodiment, and in addition to the resistance value of the entire probe 15 becoming smaller, the density of the current flowing through the probe 15 is higher than that in the vicinity of the medium facing surface. Since the inner part is smaller, it is possible to suppress heat generation of the entire probe 15, and as a result, a larger high-frequency tunnel current can be passed, and a larger reproduction signal output can be obtained.

<Thirteenth Embodiment> FIG. 19 is a block diagram of a magnetic recording / reproducing apparatus according to a thirteenth embodiment.
Similar to the seventh embodiment described with reference to FIG. 13, the tunnel current is prevented from changing according to the surface waviness and the surface unevenness of the magnetic recording medium 11.

In this embodiment, a high frequency current detecting resistor 51 is inserted between the probe 15 and the high frequency voltage source 42, and the high frequency voltage across the resistor 51 is detected by a detection circuit 52 (eg, peak detection circuit). After being detected, it is input to the low pass filter 53. The output signal of the low-pass filter 52 has a difference (error) from the target signal, which is a voltage value appearing at both ends of the high-frequency current detection resistor 51 when a predetermined target high-frequency tunnel current flows, and this error is P
It is input to the ID controller (proportional-integral-derivative controller) 54.
By controlling the output voltage of the high frequency voltage source 42 by the output signal of the PID controller 54, the high frequency tunnel current is held constant.

If the magnetic recording medium 11 has a surface waviness or a surface irregularity, the tunnel current changes greatly.
Significant fluctuations occur in the reproduced signal. However, it can be considered that the period of these surface waviness and surface irregularities is sufficiently larger than the substantially maximum period of the signal recorded on the magnetic recording medium 11, and the amplitude fluctuation of these waviness and irregularities is large. As long as (Δy) does not significantly affect the degree of ferromagnetic resonance described above, the configuration of the present embodiment enables extremely stable high-sensitivity signal reproduction.

Next, an embodiment of a third signal reproducing method according to the present invention and a magnetic recording / reproducing apparatus based on this method will be described with reference to FIGS. 20 and 21.

As shown in FIG. 20, a very thin (about 10 nm) non-conductive non-magnetic layer 12 is provided on the recording layer 13 to form a magnetic recording medium, and a conductive layer is formed on the magnetic recording medium. If the tips of the ferromagnetic films are made to face each other so as to be in contact with or substantially in contact with each other, and a DC constant current source 61 is connected to the tips, a space between the probe 15 and the recording layer 3 is formed. A tunnel current Jt having the same value as the constant current 61 flows through the non-magnetic layer 12. The non-conductive non-magnetic layer 12 may be an insulator or a semiconductor layer. The tunnel current Jt and the applied voltage V applied to the probe 15 by the constant current source 61 have the relationship shown in FIG.

Here, assuming that the applied voltage V is constant, the tunnel current Jt changes according to the angle θ formed by the magnetization of the probe 15 and the magnetization of the recording layer 13. When this angle θ changes, as shown in FIG. 3, the electrical resistance Rt of the nonmagnetic layer 12 (or the electrical conductance G which is the reciprocal thereof).
t) also changes, and the magnetic tunnel effect occurs as in the first signal reproducing method described above. Typically,
The electric resistance Rt is minimum when the magnetization of the probe 15 and the magnetization of the recording layer 13 are parallel (θ = 0 ° or 360 °), and is maximum when anti-parallel (θ = 180 °).

Therefore, the probe 15 is moved relative to the magnetic recording medium while the probe 15 is in contact with the magnetic recording medium having the recording magnetization formed on the recording layer 13, and the constant current source 6 is used.
When a constant current is supplied to the probe 1 by means of 1, the voltage (voltage drop due to the resistance Rt) V generated between the probe 15 and the recording layer 13 according to the recording magnetization of the recording layer 13 as shown in FIG.
Changes like ΔV. Therefore, by detecting this voltage change ΔV, the magnetization of the recording layer 13, that is, the signal recorded on the magnetic recording medium can be reproduced.

The above is the principle of the third signal reproducing method according to the present invention. In this case, the area where the tunnel current flows is substantially equal to the area where the probe 15 faces the magnetic recording medium. Therefore, by reducing the thickness of the probe 1 and the area of the probe 15 facing the medium, a high reproduction resolution can be easily obtained.

The magnetic tunnel effect described above is obtained by the probe 15
The distance d between the recording layer 13 and the recording layer 13 is in the range of 0 <d ≦ 50 nm. Furthermore, the change ΔR / R in the electrical resistance value between the probe 15 and the recording layer 13 according to the angle θ formed by the probe 15 and the magnetization of the recording layer 13 is as follows: The range is almost constant. Therefore, if the magnetization of the probe 15 is fixed and a constant tunnel current is made to flow between the probe 15 and the recording layer 13 by the constant current source 61,
As long as the fluctuation of d is sufficiently small, the voltage change ΔV between the probe 15 and the recording layer 13 according to the change of the magnetization recorded in the recording layer 13 can be stably detected without being influenced by this fluctuation. You can

FIG. 20 shows a schematic structure of a magnetic recording / reproducing apparatus based on the third signal reproducing method. Basically, the first embodiment shown in FIG. 5 is used except that the constant current source 61 is used.
It is similar to the embodiment. That is, the magnetic recording medium 11
Has a structure in which a soft magnetic layer 14, a perpendicular recording layer 13, and a nonmagnetic layer 12 are sequentially stacked on a medium substrate (not shown). The tip of the probe 15 made of a conductive ferromagnetic film is in contact with the magnetic recording medium 11. The easy axis of magnetization of the probe 15 is set in the longitudinal direction of the magnetic recording medium 11.
Is oriented vertically to the plane of. At least one of the perpendicular recording layer 13 and the soft magnetic layer 14 is electrically grounded. A constant current source 61 and an amplifier 62 are connected to the probe 15.

In such a structure, when a constant DC current is supplied from the constant current source 61 to the probe 15, a tunnel having the same value as the current value of the constant current source 61 is tunneled between the probe 15 and the perpendicular recording layer 13. An electric current flows. When the probe 15 and the magnetic recording medium 11 are brought into substantially contact with each other and both are relatively moved in the recording track longitudinal direction indicated by the arrow A, the probe 15 and the recording layer are changed according to the change of the recording magnetization of the perpendicular recording layer 13. The electric resistance Rt between the electrodes 13 changes, and the voltage between the probe 15 and the recording layer 13 changes accordingly. This voltage change is amplified by the amplifier 62 and taken out as a reproduction signal.

Here, as the non-conductive non-magnetic layer 12, a film of Al ₂ O ₃ , Si ₃ N ₄ , C (diamond) or the like can be used if it is an insulating material, and if it is a semiconductor material. A Ge-based film, a Si-based film, or the like can be used. As the perpendicular recording layer 13, CoCr-based, CoPt-based,
Fe as the SmCo-based ferromagnetic film and the soft magnetic layer 14
Ferromagnetic films of Co type and Co type can be used respectively. As the probe 15, Fe or Fe-based or Co
A ferromagnetic film such as a system can be used.

According to this embodiment, since the linear resolution of reproduction is determined by the film thickness t of the probe 15, a high linear resolution can be easily obtained. For example, if the recording is performed at a sufficiently high density, a reproduction line resolution of 400 to 500 kFCI can be obtained by setting the film thickness t to 50 nm or less, preferably 20 nm or less. The value of this reproduction line resolution corresponds to 5 to 10 times the value obtained in the prior art.

Further, since the probe 15 has an extremely thin film thickness and a simple structure, the processing is easy and the processing accuracy can be high. Therefore, it is extremely easy to narrow the track of the probe 15 to a submicron order or less.
It is possible to increase the manufacturing yield of the reproducing element including 5 as a main element.

Further, the distance between the probe 15 and the perpendicular recording layer 13 is set to 10 nm or less, and the value of the detection resistor 16 is set to 100 Ω or less so that the tunnel current density is 1 × 10.
¹¹ [A / m ² ] When the voltage applied to the surface of the probe 15 facing the magnetic recording medium 11 is adjusted to be ¹¹ [A / m ² ] or more, signal reproduction is performed with extremely high sensitivity, high SN ratio, and high signal frequency band. It can be carried out. Therefore, the areal recording density of the magnetic recording device can be dramatically improved as compared with the conventional technique.

In the present embodiment, the magnetization of the probe 15 is provided with sufficient anisotropy so that it is not moved by the signal magnetic field received from the magnetic recording medium 11 in order to avoid an unstable operation of the reproduction signal output. It is desirable to take measures such as keeping.

Further, although the vertical recording method has been described in this embodiment, the present invention can be applied to the longitudinal recording method and the lateral recording method.

Next, the fourth signal reproducing method according to the present invention will be described with reference to FIG. The fourth signal reproducing method is basically the same as the second signal reproducing method described with reference to FIG. 14, except that a high frequency constant current source 70 is used instead of the high frequency voltage source 42. That is, FIG.
As shown in (a), it is very thin (1
A magnetic recording medium 11 is formed by providing a non-conductive non-magnetic layer 12, and a tip 15 is formed on the magnetic recording medium 11 so that a probe 15 made of a conductive ferromagnetic film is brought into contact or substantially contact with the magnetic recording medium 11. To face each other. Here, when a high frequency constant current source 70 is connected to the probe 15 and a constant current of a predetermined high frequency is flown, a constant high frequency tunnel is formed between the probe 15 and the recording layer 13 via the non-magnetic layer 12. An electric current flows. The non-conductive non-magnetic layer 12 may be an insulator or a semiconductor layer.

The constant high-frequency tunnel current thus flowing causes a high-frequency magnetic field Hrf as shown in FIG. 22 (b).
And the high frequency magnetic field Hrf is applied to the recording magnetization 44 of the recording layer 13 directly below the probe 15. Here, the frequency f of the high-frequency current supplied from the high-frequency constant current source 70 is set so that the recording magnetization 44 causes ferromagnetic resonance, and the probe 15 is relative to the magnetic recording medium 11 in the longitudinal direction of the recording track. When moved to, the ferromagnetic resonance condition changes according to the change of the recording magnetization 44. When the ferromagnetic resonance occurs, the recording magnetization 44 precesses in the recording layer 13 of FIG. 22C as indicated by the symbol M, and expresses high frequency magnetization.

Therefore, the detection coil 41 is provided near the probe 15.
Is arranged, the recording magnetization 44 as shown in FIG.
The high-frequency magnetic flux φrf generated by the high-frequency magnetization generated thereby is linked to the detection coil, and high-frequency induced electromotive force is generated at both ends of the detection coil 41. Since this induced electromotive force is modulated by the change in the recording magnetization 44, this induced electromotive force, that is, the output signal of the detection coil 41 is amplified, and the amplified signal is detected (for example, peak detection) to thereby detect the magnetic recording medium. The signal recorded in 11 can be reproduced.

The above is the principle of the signal reproducing method according to the third invention. Generally, the ferromagnetic resonance frequency of the recording magnetization 44 is as high as several gigahertz to 20 gigahertz. Therefore, according to this signal reproducing method, even if the size of the high frequency magnetic flux φrf itself is small, a large induced electromotive force is generated in proportion to the size of the frequency, so that a sufficiently large reproduced signal output can be obtained.

Ferromagnetic resonance occurs only in the recording magnetization 44 located immediately below the probe 15. Since the signal reproduction is performed by detecting the induced electromotive force caused by the ferromagnetic resonance, the linear resolution at the time of reproduction is almost determined by the thickness of the probe 15 in the longitudinal direction of the recording track. This means that extremely large linear resolution (linear recording density) can be obtained. That is, the same effect as the second signal reproducing method can be obtained by the fourth signal reproducing method.

[0117]

As described above, according to the present invention, not only a high linear recording density of several hundred kFCI or more can be achieved, but also a signal recorded in an extremely narrow track such as submicron order can be achieved. It becomes possible to reproduce with high sensitivity, high SN ratio and wide frequency band,
Crosstalk from adjacent recording tracks is also extremely small.
Furthermore, since the structure of the probe for reproduction is extremely simple,
The remarkable effect that the working process is extremely easy, the working accuracy is high, and the high manufacturing yield is obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first signal reproducing method according to the present invention.

FIG. 2 is a diagram showing the relationship between applied voltage and tunnel current density.

FIG. 3 is a diagram showing the relationship between the angle formed by the magnetization of the probe and the magnetization of the recording layer and the electrical resistance of the nonmagnetic insulating layer.

FIG. 4 is a diagram showing a temporal change in tunnel current density due to relative movement of a probe with respect to a magnetic recording medium.

FIG. 5 is a schematic configuration diagram of a magnetic recording / reproducing apparatus according to the first embodiment.

FIG. 6 is a side view showing a main part configuration of a magnetic recording / reproducing apparatus according to a second embodiment.

FIG. 7 is a cross-sectional view showing the main configuration of a magnetic recording / reproducing device according to third and ninth embodiments.

FIG. 8 is a sectional view showing a main configuration of a magnetic recording / reproducing apparatus according to a fourth embodiment.

FIG. 9 is an exploded perspective view showing the overall configuration of a magnetic recording / reproducing apparatus according to a fifth embodiment.

FIG. 10 is a diagram showing a configuration of a head slider according to a fifth embodiment.

FIG. 11 is a sectional view showing a mounting structure of a recording element and a reproducing element on a head slider according to a fifth embodiment.

FIG. 12 is a perspective view showing a configuration of a main part of a magnetic recording / reproducing apparatus according to sixth and twelfth embodiments.

FIG. 13 is a block diagram showing the configuration of a magnetic recording / reproducing apparatus according to a seventh embodiment.

FIG. 14 is a diagram for explaining a second signal reproducing method according to the present invention.

FIG. 15 is a schematic configuration diagram of a magnetic recording / reproducing apparatus according to an eighth embodiment.

FIG. 16 is a sectional view showing the structure of a magnetic recording / reproducing apparatus according to a tenth embodiment.

FIG. 17 is a perspective view showing a configuration of a main part of a magnetic recording / reproducing apparatus according to an eleventh embodiment.

FIG. 18 is a sectional view showing a mounting structure of a recording element and a reproducing element on a head slider in an eleventh embodiment.

FIG. 19 is a block diagram showing the configuration of a magnetic recording / reproducing apparatus according to a thirteenth embodiment.

FIG. 20 is a diagram for explaining a third signal reproducing method according to the present invention.

FIG. 21 is a diagram showing a change in voltage between the probe and the recording layer due to a change in tunnel current density due to relative movement of the probe with respect to the magnetic recording medium in the third signal reproducing method.

FIG. 22 is a diagram for explaining a fourth signal reproducing method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Probe 2 ... Nonmagnetic insulating layer 3 ... Recording layer 10 ... Medium substrate 11 ... Magnetic recording medium 12 ... Nonmagnetic insulating layer 13 ... Recording layer 14 ... Soft magnetic layer 15 ... Probes 15-1, 15-2 ... Conductive film 16 ... Current detection resistor 17 ... DC voltage source 18 ... Amplifier 19-1 and 19-2 ... Nonmagnetic insulating layer 20 ... Antiferromagnetic film 21 ... Medium facing surface 31 ... Constant voltage source 32 ... Low-pass filter 33 ... PID controller 41 ... Detection coil 42 ... High frequency voltage source 43 ... Recording track 44 ... Recording magnetization 45 ... Amplifier 46 ... Detecting circuit 47 ... Probe inner part 48 ... Insulating material 51 ... High frequency current detecting resistor 52 ... Detecting circuit 53 ... low-pass filter 54 ... PID controller 61 ... constant current source 62 ... amplifier 70 ... high frequency constant current source 101 ... magnetic disk 102 ... spindle motor 103 ... head slider 104 ... suspension 105 ... Arm 106 ... Voice coil motor 107 ... Fixed shaft 108 ... Lid 109 ... Slider surface 110 ... Slider part 111 ... Head support part 112 ... Contact part 113 ... Base end part 114 ... Head forming surface 115 ... Thin film lead wire 200 ... reproducing element 201 ... non-magnetic insulating layer 202 ... non-magnetic insulating layer 203 ... recording element 204 ... magnetic core 205 ... recording coil 206 ... magnetic gap 207 ... non-magnetic insulating layer

Claims (14)

[Claims] 1. A magnetic recording medium having a conductive recording layer is provided with a probe made of a ferromagnetic film with its tip facing to be movable relative to the magnetic recording medium, and the probe and the recording layer. Is recorded on the magnetic recording medium by applying a DC voltage between the magnetic recording medium and the magnetic recording medium, flowing a tunnel current between the tip of the probe and the magnetic recording medium, and detecting a change in the tunnel current. A signal reproducing method in a magnetic recording / reproducing apparatus characterized by reproducing a signal. 2. A magnetic recording / reproducing apparatus for recording / reproducing a signal using a magnetic recording medium having a non-conductive non-magnetic layer provided on a conductive recording layer, the tip being opposed to the magnetic recording medium. And a probe made of a ferromagnetic film provided so as to be movable relative to the magnetic recording medium, a DC voltage applying means for applying a DC voltage between the probe and the recording layer, A signal recorded on the magnetic recording medium is reproduced by detecting a tunnel current flowing through the non-magnetic layer between the tip of the probe and the recording layer by applying a DC voltage by a voltage applying unit. And a magnetic recording / reproducing apparatus. 3. A direct current voltage based on a difference between an output signal of the low pass filter and a target signal, a current detecting means for detecting the tunnel current, a low pass filter receiving an output signal from the current detecting means as an input. The magnetic recording / reproducing apparatus according to claim 2, further comprising a control unit that controls a DC voltage applied by the applying unit. 4. A magnetic recording medium having a conductive recording layer is provided with a tip made of a ferromagnetic film so that the tip is opposed to the magnetic recording medium, and the tip of the tip and the tip of the ferromagnetic film are provided. A signal recorded on the magnetic recording medium is reproduced by applying a constant tunnel current to the magnetic recording medium and detecting a change in voltage generated between the probe and the recording layer. A signal reproducing method in a characteristic magnetic recording / reproducing apparatus. 5. A magnetic recording / reproducing apparatus for recording and reproducing a signal using a magnetic recording medium having a non-conductive non-magnetic layer provided on a conductive recording layer, the tip of which faces the magnetic recording medium. And a constant current supply means connected to the probe, and a constant current supply from the constant current supply means. By detecting a change in voltage generated between the probe and the recording layer based on a constant tunnel current flowing between the tip of the probe and the recording layer via the nonmagnetic layer. ,
A magnetic recording / reproducing apparatus, comprising means for reproducing a signal recorded on the magnetic recording medium. 6. An antiferromagnetic film or a hard magnetic film for fixing the magnetization of the probe in a predetermined direction is laminated on the probe, wherein the probe is laminated. 2. The magnetic recording / reproducing apparatus according to item 1. 7. A head section comprising a recording element for recording a signal on a rotating disk-shaped magnetic recording medium and a reproducing element including at least the probe for reproducing a signal recorded on the magnetic recording medium, A head slider having a head portion mounted thereon, wherein the head slider faces the magnetic recording medium such that a fluid force generated by a dynamic pressure effect of a gas flow accompanying the rotation of the magnetic recording medium acts. And a surface which is connected to the slider portion, supports the head portion so that its tip is in contact with the magnetic recording medium, has a smaller mass than the slider portion, and faces the magnetic recording medium. 7. The magnetic recording medium according to claim 2, wherein the area of the magnetic recording medium is a head supporting portion smaller than the area of the slider surface. Raw equipment. 8. A magnetic recording medium having a conductive recording layer is provided with a probe made of a ferromagnetic film with its tip facing to be movable relative to the magnetic recording medium, and the probe and the recording layer. By applying a high-frequency voltage between the magnetic recording medium and the tip of the probe to cause a ferromagnetic resonance in the recording magnetization of the recording layer immediately below the probe. And reproducing a signal recorded in the magnetic recording medium by detecting a high frequency magnetic flux generated from the recording magnetization due to the ferromagnetic resonance. How to play. 9. A magnetic recording / reproducing apparatus for recording and reproducing a signal using a magnetic recording medium having a non-conductive non-magnetic layer provided on a conductive recording layer, the tip of which faces the magnetic recording medium. The probe formed of a ferromagnetic film is provided so as to be movable relative to the magnetic recording medium, and the magnetization in the recording layer immediately below the probe is between the probe and the recording layer. A high-frequency voltage applying means for applying a high-frequency voltage having a frequency that causes ferromagnetic resonance, and a high-frequency voltage applying means provided near the probe so as to be movable relative to the magnetic recording medium together with the probe. The change in the high frequency magnetic flux generated by the recording magnetization of the recording layer is detected based on the high frequency tunnel current flowing between the tip of the probe and the recording layer by the application of Detection signal And a detection coil that outputs a detection signal output from the detection coil to obtain a reproduction signal corresponding to a signal recorded in the magnetic recording medium. Playback device. 10. A probe made of a ferromagnetic film is provided so as to be movable relative to the magnetic recording medium with a tip facing a magnetic recording medium having a conductive recording layer. By passing a constant high-frequency tunnel current between the magnetic recording medium and the magnetic recording medium, a ferromagnetic resonance is generated in the recording magnetization of the recording layer immediately below the probe, and the ferromagnetic resonance causes the recording magnetization to change from the recording magnetization. A signal reproducing method in a magnetic recording / reproducing apparatus, characterized in that a signal recorded in the magnetic recording medium is reproduced by detecting a generated high frequency magnetic flux. 11. A magnetic recording / reproducing apparatus for recording and reproducing a signal using a magnetic recording medium having a non-conductive non-magnetic layer provided on a conductive recording layer, the tip of which faces the magnetic recording medium. Then, a probe formed of a ferromagnetic film is provided so as to be movable relative to the magnetic recording medium, and the magnetization in the recording layer directly below the probe causes ferromagnetic resonance. A high frequency constant current supply means for supplying a high frequency constant current of a frequency to be generated, and a high frequency constant current supply means provided near the probe so as to be movable relative to the magnetic recording medium together with the probe. The high-frequency magnetic flux is detected by detecting a change in the high-frequency magnetic flux generated from the recording magnetization of the recording layer based on a constant high-frequency tunnel current flowing between the tip of the probe and the recording layer by supplying a constant current. Against changes A detection coil for outputting the detected signal, and detection means for detecting the detection signal output from the detection coil to obtain a reproduction signal corresponding to the signal recorded on the magnetic recording medium. Magnetic recording / reproducing device. 12. The probe is composed of at least two conductive films arranged along a relative movement direction with respect to the magnetic recording medium, and the conductive films are disposed in the vicinity of a surface facing the magnetic recording medium. The detection coil has a predetermined space in the moving direction, is electrically connected to each other at other portions, and the detection coil is arranged between the two conductive films near the surface facing the magnetic recording medium. The magnetic recording / reproducing apparatus according to claim 9 or 11, characterized in that. 13. A head comprising a recording element for recording a signal on a rotating disk-shaped magnetic recording medium and a reproducing element including at least the probe and a detection coil for reproducing a signal recorded on the magnetic recording medium. And a head slider on which the head is mounted, the head slider and the magnetic recording medium such that a fluid force generated by a dynamic pressure effect of a gas flow accompanying the rotation of the magnetic recording medium acts. A slider portion having slider surfaces facing each other, the head portion being supported by the slider portion so as to contact the head portion with the magnetic recording medium, and having a smaller mass than the slider portion, and the magnetic recording medium. 13. The head supporting portion having an area of a surface facing the head supporting area smaller than that of the slider surface. Item 6. A magnetic recording / reproducing apparatus according to Item 1. 14. A current detection means for detecting the tunnel current, a detection circuit for detecting an output signal from the current detection means, a low-pass filter having an output signal of the detection circuit as an input, and an output of the low-pass filter. 14. The magnetic device according to claim 9, further comprising: a control unit that controls a high frequency voltage applied by the high frequency voltage applying unit based on a difference between a signal and a target signal. Recording / playback device.