JPH076416A - Information processing equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an information processing device to which a technique of a scanning tunneling microscope is applied, which enables accurate and high-speed access to a recording medium. [Arrangement] Magnets 1 and 2 for forming a magnetic field having a magnetic gradient in the in-plane direction of a recording surface 7 of a recording medium 6, and a magnetic field for detecting a magnetic field provided on a cantilever 15 to which a probe 10 is fixed. An information processing apparatus including a sensor 9 and a drive mechanism 17 for controlling the position of the probe 10 in the in-plane direction of the recording surface 7 based on a signal from the magnetic sensor 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus for recording and reproducing information using the principle of a scanning tunneling microscope.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter referred to as "STM") has been developed which can directly observe the electronic structure of surface atoms of a conductor. Since the STM can operate in vacuum, air, and liquid and can perform high-resolution measurement in real space regardless of whether it is single crystal or amorphous, it is expected to have a wide range of applications.

In such STM technology, a voltage is applied between the probe and the conductive substance to apply the probe to the surface of the conductive substance by 1 n.
The fact that a tunnel current flows through the probe when it is brought close to a distance of about m is used. Since this current is very sensitive to changes in the distance between the two, by scanning the probe so as to keep this constant, it is possible to draw the real space structure of the surface of the conductive material, and at the same time, obtain information on the electronic structure. Can also be read. The resolution in the in-plane direction at this time is about 0.1 nm.

Therefore, if the principle of STM is applied, atoms,
High-density recording / reproduction on a molecular order can be performed.
Various methods have been proposed as recording / reproducing methods in this case. For example, a method has been proposed in which recording / reproducing is performed by using STM using a material having a memory effect with respect to switching characteristics of voltage / current as a recording layer, for example, a thin film layer of π-electron organic compound or chalcogen compound. (For example,
JP-A-63-161552, JP-A-63-161
553 publication). In this method, it is necessary to accurately move the probe used for recording / reproducing to a desired position on the recording medium.

The position control in this case is roughly as follows. Since the recording size is on the atomic order, first place the probe on the desired recording site on the recording medium, the piezoelectric element,
The probe is moved in a direction parallel to the recording surface of the recording medium in the range of 10 mm to 1 μm (hereinafter referred to as “coarse movement”) by a stepping motor or the like, and the probe is further moved from 1 μm to 0 by another driving mechanism such as a piezoelectric element. It is moved (hereinafter referred to as “fine movement”) in the range of 1 nm atomic order. The position control for both the coarse movement and the fine movement is performed by detecting a reference (hereinafter, referred to as “reference scale”) regarding the position set on the recording medium. For example, it has been proposed to use the unevenness formed on the surface of the recording medium as a reference scale.

[0006]

Conventionally, PZT (lead zirconate titanate), which has a large amount of displacement, has been widely used as a piezoelectric element for moving a probe and a recording medium. The PZT has a linear voltage-displacement characteristic with respect to a minute displacement, and can precisely control the position of the probe and the like. However, when the amount of displacement increases, the voltage of PZT-
There is a problem that the displacement characteristic becomes non-linear and it becomes difficult to control the position of the probe or the like with high accuracy.

On the other hand, in order to specify an arbitrary point on the surface of the recording medium, at least two reference scales independent of each other are required. For example, when the shape of the recording medium is circular, in order to specify an arbitrary point on the recording surface, reference coordinates relating to the distance r from the center of the circle and reference coordinates relating to the angle θ are required as shown in FIG. .

When such a reference scale is formed on the surface of the recording medium, the total area of the area in which information can be written is reduced by the area occupied by the reference scale, and the storage capacity of the recording medium is suppressed. There was a point.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. In an information processing apparatus to which the STM technology is applied, the accuracy of position control of the probe or the like can be improved even if the reference scale formed on the recording medium is reduced. It is an object of the present invention to provide a positioning mechanism that does not deteriorate.

[0010]

In order to achieve the above object, the present invention firstly applies a voltage between a recording medium and a probe provided facing the recording medium. In the information processing apparatus capable of recording information by means of the above, means for forming a magnetic field having a magnetic gradient in the in-plane direction of the recording surface of the recording medium, means for detecting the magnetic field, and signals from the magnetic field detecting means. An information processing apparatus comprising means for controlling the position of the probe with respect to the in-plane direction based on

Secondly, the information processing apparatus according to the first aspect of the present invention is characterized in that the magnetic field forming means comprises a permanent magnet and / or an electromagnet.

Thirdly, there is provided the above-mentioned first or second information processing apparatus of the present invention, wherein the magnetic field detecting means is a Hall element.

Fourthly, the information processing apparatus according to any one of the first to third inventions of the present invention is characterized in that the recording surface of the recording medium is circular.

Fifthly, the above-mentioned fourth information processing apparatus of the present invention is characterized in that the recording medium rotates about a normal line of the recording surface passing through the center of the circular recording surface as a rotation axis.

Sixth, there is provided the information processing apparatus according to the fifth aspect of the present invention, wherein the magnetic gradient of the magnetic field is formed symmetrically with respect to the rotation axis.

Seventh, the position control means of the probe is
The information processing apparatus according to any one of the fourth to sixth aspects of the present invention, wherein the probe is scanned in a radial direction of the circular recording surface,

Eighth, the information processing apparatus according to any one of the first to seventh inventions, characterized in that the magnetic field detecting means and the probe are fixed on the same support.

Ninth, the above-mentioned eighth information processing apparatus of the present invention is characterized in that the support is a cantilever and the probe is fixed to the free end of the cantilever.

Tenth, in the information processing apparatus according to the first to ninth aspects of the present invention, a pulse voltage is applied between the recording medium and the probe to cause a selective change on the surface of the recording medium. Information is recorded by reproducing the information, and a current flowing through the probe when a voltage that does not cause a selective change in the recording medium is applied between the recording medium and the probe is detected by the current detecting means. It is an information processing device characterized by performing by detecting,

Eleventh, the current flowing through the probe is
A tenth aspect of the present invention, which is a tunnel current.
Is an information processing device of

Twelfthly, in the information processing apparatus according to the ninth aspect of the present invention, by applying a pulse voltage between the recording medium and the probe, a selective change is caused on the surface of the recording medium to generate information. Information is recorded using a cantilever deformation detecting means including means for irradiating the cantilever with laser light and means for detecting reflected light of the laser light from the cantilever. It is a processing device.

According to the present invention, by using the magnetic gradient formed in the in-plane direction of the recording surface of the recording medium as one of the reference scales, the reference scale that must be formed on the recording medium itself is only in the uniaxial direction. You can

Hereinafter, a configuration example of the present invention will be shown to explain the principle of position control using a magnetic gradient as a reference scale.

FIG. 1 shows a schematic configuration example of an information processing apparatus of the present invention. In the figure, reference numerals 1 and 2 denote conical trapezoidal magnets. The upper surfaces 3 and 4 of the truncated cones of the magnets 1 and 2 are opposed to each other, and the geometric rotation axes of the magnets 1 and 2 are on the same straight line 5. Further, the surfaces 3 and 4 of the magnets 1 and 2 have an N pole and an S pole, respectively.

Reference numeral 6 denotes a disk-shaped recording medium, which is located in the gap between the surfaces 3 and 4. 7 is a circular recording surface,
The center 8 of the circular recording surface is on the straight line 5. Recording surface 7
The normal line of is parallel to the straight line 5.

The magnetic field formed by the magnets 1 and 2 between the surfaces 3 and 4 has an axially symmetric magnetic gradient with respect to the straight line 5, and the magnitude of the magnetic field becomes smaller as the distance from the straight line 5 increases, and the recording surface 7 The relationship between the distance r from the point 8 and the magnitude B of the magnetic field is schematically shown in FIG. As described above, the magnitude B of the magnetic field depends on the distance r, and the equimagnetism curve on the recording surface 7 is a circle centered on the point 8 as shown in FIG. 3B.

That is, since the recording surface 7 exists under a non-uniform magnetic field which is point-symmetric with respect to the point 8, the magnetic field magnitude B _A at any point A on the recording surface 7 and the points A and 8 are given. The distance r _A between them has a one-to-one relationship.

By using this property of the magnetic field, the magnetic gradient formed by the magnets 1 and 2 can be calculated by calculating the radius r on the circular recording surface 7.
It can be used as a reference scale for direction.

For example, by searching in advance the relationship between the radius r and the magnitude B of the magnetic field, finding a point on the circumference of an arbitrary radius r _A centered on the point 8 on the recording surface 7 This is possible by detecting the point where the magnitude of the magnetic field corresponding to the position of the radius r _A is B _A by the magnetic sensor 9 which is a detecting means. On the other hand, if the magnetic sensor 9 traces the area of the magnetic field magnitude B _A on the recording surface 7, the locus drawn by the magnetic sensor 9 is the point 8 corresponding to the magnetic field magnitude B _A.
Is a circle centered at and having a radius r _A.

Therefore, the relative positional relationship between the magnetic sensor 9 and the recording / reproducing probe 10 is stored in advance,
By detecting the position in the radius r direction of the recording surface 7 of the magnetic sensor 9, the radial position of the probe 10 in the recording surface 7 can be automatically known.

As described above, according to the preferred embodiment of the present invention, when the recording / reproducing probe is positioned, the magnetic gradient in the in-plane direction of the recording surface formed in the space near the surface of the recording medium is used as the reference scale. The proportion of the reference scale provided on the recording medium itself in the recording surface can be reduced, and as a result, the proportion of the recordable area on the recording surface can be increased, and a large-capacity information processing device can be realized. It

The means for forming the magnetic gradient in the present invention is not particularly limited in shape, arrangement, number and kind of magnets as long as the magnetic gradient can be formed in the in-plane direction of the recording surface.

Next, the components of the information processing apparatus of the present invention other than those described above will be described with reference to FIG.

The recording medium 6 is a recording layer 1 having a memory function.
The recording medium driving mechanism 14 can rotate the straight line 5 as a rotation axis.

The probe 10 faces the recording surface 7.
Reference numeral 15 is a cantilever that supports the probe 10, and 16 is a structure that supports the cantilever 15. Reference numeral 17 denotes a drive mechanism attached to the structure 16, which can scan the probe 10 in the radial direction of the recording surface 7.

The magnetic sensor 9 is fixed to the cantilever 15 and measures the magnetic field on the recording surface to detect the position of the probe 10.

At the time of recording / reproducing by this apparatus, first, the electrode 1
The voltage applying circuit 18 applies a voltage to the extent that a tunnel current flows between the probe 2 and the probe 10, and the tunnel voltage is detected by the current-voltage conversion circuit 19 so that the value becomes constant. The probe 10 is driven by 23 to control the distance between the recording layer 11 and the probe 10.

At the time of recording information, the recording medium 6 and the probe 10 are relatively scanned, and a predetermined voltage is applied between the electrode 12 and the probe 10 at a desired position on the recording surface 7 by the voltage application circuit 18. Then, recording bits are formed on the recording layer 11. The recording bit may be a change in conductivity formed in the recording layer 11 or a change in morphology of the recording layer 11, but is not particularly limited.

When reproducing information, the probe 10 is scanned on the recording surface 7 while keeping the distance between the recording layer 11 and the probe 10 constant by the above method. At that time, probe 1
The recording bit can be detected because the tunnel current detected by the current-voltage conversion circuit 19 changes depending on whether 0 scans the recording bit or other areas. That is, the recorded bits can be reproduced.

The relative scanning between the recording medium 6 and the probe 10 is performed by the drive mechanism 17 based on a signal from the magnetic sensor 9 sent via the drive circuit 21 in the radial direction of the recording surface 7. In the direction perpendicular to the radial direction, the probe 10 is, for example, a reference scale radially formed on the recording medium around the point 8 or a reference scale spirally formed on the recording medium starting from the point 8 in the direction perpendicular to the radial direction. The recording medium drive mechanism 14 is driven by a signal from the drive circuit 20 based on the detection signal. Further, the apparatus is centrally controlled by the computer 22.

[0041]

The present invention will be described in detail with reference to the following examples.

Embodiment 1 In this embodiment, an information processing apparatus of the present invention as shown in FIG. 1 is constructed.

In this embodiment, Sm-Co is used as the magnets 1 and 2.
Type permanent magnet was used. The magnets 1 and 2 are frustoconical and are congruent with each other. The upper surfaces 3 and 4 of the magnets 1 and 2 are opposed to each other, and the surfaces 3 and 4 have an N pole and an S pole, respectively. The geometric rotation axes of the magnets 1 and 2 are on the same straight line 5.

Next, the recording medium 6 was fixed to the recording medium driving mechanism 14 provided in the gap between the surfaces 3 and 4 of the magnets 1 and 2. The drive mechanism 14 can rotate about the straight line 5 as a rotation axis. The center 8 of the circular recording surface 7 of the recording medium 6 is fixed on the recording medium drive mechanism 14 so that the center 8 passes through the straight line 5 and the normal line of the recording surface 7 is parallel to the straight line 5.

The substrate 13 used in this example is a circular quartz glass substrate, and the electrode 12 is Au having a thickness of 1000Å formed on the substrate 13 by the vacuum deposition method. The recording layer 11
Squalylium-bis-6-octylazulene (SOAZ) is used as the Langmuir projector (L
It was prepared by laminating a monolayer of SOAZ on the two-layer electrode 12 by the method B) (see Japanese Patent Laid-Open No. 63-161552).

The magnetic field formed by the magnets 1 and 2 in the gap between the surfaces 3 and 4 forms an axisymmetric magnetic gradient with respect to the straight line 5, and the magnitude of the magnetic field becomes smaller as the distance from the straight line 5 increases.

Therefore, on the recording surface 7, the isomagnetic curve is a circle centered on the point 8 on the recording surface 7, and the magnitude of the magnetic field is the point 8.
It gets smaller as you move away from it. That is, since the recording surface 7 exists under a nonuniform magnetic field, an arbitrary point A on the plane 7
The magnitude B _A of the magnetic field at and the distance r _A between the point A and the point 8 have a one-to-one relationship. In this embodiment, the magnetic gradient formed by the magnets 1 and 2 is used as a reference scale in the radial direction on the circular recording surface 7.

The probe 10 is fixed to the free end of the cantilever 15. The probe 10 faces the recording surface 7. The cantilever 15 is fixed to the structure 16. The major axis direction of the cantilever 15 is orthogonal to the radial direction of the circular recording layer. Reference numeral 17 denotes a drive mechanism attached to the structure 16, which can scan the probe 10 in the radial direction of the recording surface 7.

The magnetic sensor 9 is composed of a Hall element, and is fixed to the back side of the surface of the cantilever 15 on which the probe 10 is fixed. The magnetic sensor 9 measures the magnetic field at the position of the probe 10.

A method of positioning the recording / reproducing probe 10 in the radial direction of the recording surface 7 using the magnetic gradient will be described below.

In this embodiment, the relationship between the distance r from the point 8 and the magnitude B of the magnetic field is used as a reference in advance for the computer 2
Remember in 2.

When the probe 10 was to be accessed on the recording surface 7 from the point 8 on the circumference of an arbitrary distance r _A , the following position control was performed.

First, the magnitude B _A of the magnetic field at the position of the distance r _A is read from the computer 22. Next, the magnetic sensor 9 is driven by the driving mechanism 17 until the difference between the magnitude of the magnetic field measured by the magnetic sensor 9 and B _A becomes 0.
Scan in the radial direction. The position where the difference in the magnitude of the magnetic field becomes 0 is the point on the recording surface 7 at a distance r _A from the point 8. By thus accessing the magnetic sensor 9 at a position having a desired magnetic field strength, the probe 10 can be accessed at a desired position.

On the contrary, the magnetic field is measured by the magnetic sensor 9,
By comparing with the reference, it is possible to know how far the probe 10 is from the point 8 on the recording surface 7 in the radial direction.

The magnetic gradient thus formed in the space near the recording medium 6 can be used as a reference scale in the radial direction of the recording surface 7.

In this embodiment, the probe 10, the cantilever 15, the cantilever supporting structure 16 and the magnetic sensor 9 are formed by a known micromechanics technique (see, for example, KE Petersen, Proc.
IEEE, 70, 420 (1982)). The cantilever 16 is a piezoelectric bimorph type cantilever.
The cantilever can be deformed in the direction perpendicular to the recording surface 7 by the voltage from the cantilever driving circuit 23, and the probe 10 can be displaced in association with the movement of the cantilever 16.

Next, a recording / reproducing operation using this apparatus will be described.

Recording of information on the recording layer 11 was performed by this apparatus by the following method. First, after the probe 10 is accessed to a desired position on the recording surface 7, the current I _T flowing in the probe 10 is applied to the current-voltage conversion circuit 19 while the voltage application circuit 18 applies a voltage of + 1.5V to the probe 10. And the current value I _T is 10 ⁻⁸ [A] ≧ I _T ≧ 10
The distance between the surface of the probe 10 and the surface of the recording layer 11 was adjusted using the cantilever 15 so as to be ^-10 [A]. Then, with the distance held, the probe 10 is set to the + side,
A voltage as shown in FIG. 4 is applied between the probe 10 and the electrode 12 by the voltage applying circuit 18 with the electrode 12 on the negative side. After applying the voltage, the recording layer 11 facing the probe 10
The electrical conductivity of the micro-region is increased and the state is maintained. The recording bit was written by the above operation. The recording bit string based on the recording information was formed by performing the writing operation while moving the probe 10 on the recording layer 11 by the driving mechanisms 14 and 17.

The recorded information was reproduced by the following method. Probe 1 to which + 1.5V voltage is applied
0 is scanned over the recording layer 11 while maintaining a constant distance from the recording layer 11 by the above method. Since the recording bit portion has higher conductivity than the other regions, when the probe 10 scans the recording bit portion, the current flowing through the probe 10 is compared with that when the probe 10 scans the portion other than the recording bit portion. And grow bigger. Information was reproduced by detecting this change in current value with the current-voltage conversion circuit 19.

In this embodiment, the magnetic gradient formed in the space near the recording medium 6 is used as the reference scale in the radial direction of the circular recording surface 7, so that the amount of the reference scale formed on the recording medium 6 itself is reduced. The information recordable area could be increased by 30%. Further, in this embodiment, the positioning accuracy in the radial direction could be 0.1 μm and the access speed could be 10 ms or less.

Particularly large displacement in the radial direction (coarse movement)
With regard to the above, the position of the probe can be controlled more accurately than before, and at the same time, high-speed access is possible.

In addition, since it is possible to reduce the amount of reference scales that must be formed on the recording medium 6 itself,
The recording medium manufacturing time was shortened.

Example 2 In this example, electromagnets (see FIG. 5) were used as the magnets 1 and 2 to form a magnetic gradient. Specifically, the coil 25 is wound around the iron core 24 that is congruent with the permanent magnet used in Example 1 to form an electromagnet. The configuration and recording / reproducing principle of the device other than this are the same as those in the first embodiment.

As in the first embodiment, by using the magnetic gradient formed in the space near the recording medium 6 as the reference scale in the radial direction of the circular recording layer 11, the amount of the reference scale formed on the recording medium 6 itself is adjusted. The area where information can be recorded can be increased by 30%.

Further, as in the first embodiment, the position of the probe can be accurately controlled even for a large amount of displacement in the radial direction, and high-speed access is possible.

Furthermore, since the amount of the standard scale that must be formed on the recording medium 6 itself can be reduced, the recording medium manufacturing time can be shortened.

Embodiment 3 FIG. 6 shows a schematic block diagram of an information processing apparatus according to this embodiment. In this embodiment, information recording is performed by the STM as in the first embodiment.
An apparatus for reproducing recorded information according to the principle of AFM and the principle of AFM was constructed.

In this example, the surface layer of the electrode 12 made of gold was used as the recording layer 11. A known optical lever method is used to measure the displacement of the recording surface 7 of the probe 10 in the normal direction. Therefore, the semiconductor laser 26 irradiates the upper surface of the cantilever 15 with laser light so that the laser light reflected from the cantilever 15 can be received by the two-divided photodiode 27. The rest of the configuration is the same as the configuration of the information processing apparatus in the first embodiment.

In this example, information was written in the recording layer by the following method. A voltage having a pulse width of several μsec and a wave height of several volts is applied between the probe 10 and the recording layer 11 made of gold using a voltage application circuit 18 to form a convex portion having a diameter of 10 nm and a height of 2 nm on the recording layer surface. Formed. This is the recorded bit.

Bit reproduction by the AFM technique was performed by the following method. The probe 10 is brought close to the recording layer 11 to the extent that an atomic force acts between the recording layer 11 and the probe 10, and recording is performed with the probe 10 while applying feedback so that the atomic force acting on the probe 10 becomes constant. When the layer 11 is relatively scanned, the probe 10 moves up and down according to the unevenness of the surface of the recording layer 11. This probe 10
The movement of the cantilever 10 that is interlocked with the vertical movement of is detected by the principle of light. By this method, the recording bit formed in a convex shape is detected.

As in the first embodiment, by using the magnetic gradient formed in the space near the recording medium 6 as the reference scale in the radial direction of the circular recording layer 11, the amount of the reference scale formed on the recording medium 6 itself is reduced. It was possible to increase the information recordable area by 30%.

Further, as in the first embodiment, the probe can be position-controlled accurately even for a large displacement in the radial direction, and high-speed access is possible.

Further, since the amount of the reference scale that must be formed on the recording medium 6 itself can be reduced, the recording medium manufacturing time can be shortened.

[0074]

As described above, the present invention has the following effects.

(1) One of two mutually independent reference scales necessary for designating an arbitrary point on the recording medium can be formed in the space near the recording medium. As a result, the area occupied by the reference graduations that must be formed on the recording medium itself can be reduced and the capacity can be increased.

(2) The position of the probe can be accurately controlled even for a large amount of displacement in the radial direction of the recording surface, and high-speed access is possible.

(3) Since it is possible to reduce the amount of reference scales that have to be formed on the recording medium itself, it is possible to reduce the ratio of the reference scale forming steps in the recording medium manufacturing process, which reduces the manufacturing time. It was possible to shorten the manufacturing cost and reduce manufacturing costs.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of an information processing apparatus of the present invention.

FIG. 2 is a diagram showing how to set reference coordinates on a circular recording surface.

FIG. 3 is a diagram for explaining a magnetic gradient according to the present invention.

FIG. 4 is a pulse voltage waveform diagram used during recording.

5 is a schematic diagram of an electromagnet used in Example 2. FIG.

FIG. 6 is a schematic configuration diagram of an information processing apparatus of the present invention shown in a third embodiment.

[Explanation of symbols]

 1, 2 Magnets 3, 4 Magnetic pole surface 5 Rotation axis 6 Recording medium 7 Recording surface 8 Recording surface center 9 Magnetic sensor 10 Probe 11 Recording layer 12 Electrode 13 Substrate 14 The medium driving mechanism 15 Cantilever (support) 16 Structure 17 Structure Body drive mechanism 18 Voltage application circuit 19 Current-voltage conversion circuit 20 Recording medium drive mechanism drive circuit 21 Structure drive mechanism drive circuit 22 Computer 23 Cantilever drive circuit 24 Iron core 25 Coil 26 Semiconductor laser 27 Photodiode

Claims (12)

[Claims] 1. An information processing apparatus capable of recording information by applying a voltage between a recording medium and a probe provided facing the recording medium, wherein an in-plane direction of a recording surface of the recording medium. And a means for forming a magnetic field having a magnetic gradient, a means for detecting the magnetic field, and a means for controlling the position of the probe with respect to the in-plane direction based on a signal from the magnetic field detecting means. Information processing equipment. 2. The information processing apparatus according to claim 1, wherein the magnetic field forming means includes a permanent magnet and / or an electromagnet. 3. The information processing apparatus according to claim 1, wherein the magnetic field detecting means is a Hall element. 4. The information processing apparatus according to claim 1, wherein the recording surface of the recording medium is circular. 5. The information processing apparatus according to claim 4, wherein the recording medium rotates about a normal line of the recording surface passing through a center of the circular recording surface as a rotation axis. 6. The information processing apparatus according to claim 5, wherein the magnetic gradient of the magnetic field is formed symmetrically with respect to the rotation axis. 7. The information processing apparatus according to claim 4, wherein the probe position control means scans the probe in a radial direction of the circular recording surface. 8. The magnetic field detecting means and the probe are fixed on the same support.
The information processing device according to any one of to 7. 9. The information processing apparatus according to claim 8, wherein the support is a cantilever, and the probe is fixed to a free end of the cantilever. 10. The information processing apparatus according to claim 1, wherein a pulse voltage is applied between the recording medium and the probe to cause a selective change on the surface of the recording medium to thereby record information. Is recorded, and the current flowing through the probe is detected by the current detecting means when a voltage that does not cause a selective change in the recording medium is applied between the recording medium and the probe to reproduce the information. An information processing apparatus characterized by being performed by 11. The information processing apparatus according to claim 10, wherein the current flowing through the probe is a tunnel current. 12. The information processing apparatus according to claim 9, wherein a pulse voltage is applied between the recording medium and the probe to selectively change the surface of the recording medium to record information. The information processing apparatus is characterized in that the reproduction of the information is performed using a cantilever deformation detecting means including means for irradiating the cantilever with laser light and means for detecting reflected light of the laser light from the cantilever. .