JPH10125057A - Magnetic unit employing magnetic semiconductor and magnetic information transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic unit employing a reproducible magnetic semiconductor, and a method for transferring magnetic information, in which magnetic information can be transferred along the surface of a magnetic recording medium and a large volume of magnetic information can be recorded without moving the magnetic recording medium mechanically. SOLUTION: A magnetic disc 10 comprises a substrate, a magnetic semiconductor layer 12 of InMnAs or the like formed on the substrate, a first gate electrode 13 for splitting the magnetic semiconductor layer 12 into a plurality of recording areas, and a second gate electrode 14 arranged on each recording area. The first and second gate electrodes 13, 14 are applied selectively with voltages by a voltage applying means. The magnetic semiconductor layer 12 exhibits ferromagnetism when the carrier density is high and paramagnetism when the carrier density is low. Magnetic information recorded in one recording area is transferred to another recording area by controlling the voltages being applied to the first and second gate electrodes 13, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the recording of magnetic information,
More particularly, the present invention relates to a magnetic device using a magnetic semiconductor as a recording medium and a method for transferring magnetic information.

[0002]

2. Description of the Related Art Conventionally, as a device for recording information, an element for converting information into an electric charge amount and recording such as a DRAM, and a magnetic recording for converting information into magnetism and recording such as a hard disk device, etc. There are devices.

[0003]

However, DRA
For elements such as M that record information by converting information into electric charges, although the elements are becoming finer, it is difficult to further increase the density from the structure, and it is necessary to manufacture a large-capacity recording device. Is difficult. On the other hand, a magnetic recording device such as a conventional hard disk device requires a large current to rotate a disk as a magnetic recording medium. Further, a motor for rotating the disk, a power supply for driving the motor, and the like are required, and it is difficult to reduce the size of the apparatus.

An object of the present invention is to transfer magnetic information along the surface of a magnetic recording medium, and to record or record a large amount of magnetic information without mechanically moving the magnetic recording medium. An object of the present invention is to provide a magnetic device using a magnetic semiconductor capable of reproducing information and a method for transferring magnetic information in the magnetic device.

[0005]

The above object is achieved by providing a magnetic semiconductor layer, a plurality of first gate electrodes disposed on the magnetic semiconductor layer and dividing the magnetic semiconductor layer into a plurality of recording areas, The problem is solved by a magnetic device using a magnetic semiconductor, comprising a second gate electrode formed on each recording area.

[0006] The above-mentioned problems are also solved by a substrate, a magnetic semiconductor layer formed on the substrate, and a first gate formed on the magnetic semiconductor layer and dividing the magnetic semiconductor layer into a plurality of recording areas. An electrode; a second gate electrode formed on each recording area; voltage applying means for selectively applying a voltage to the first gate electrode and the second gate electrode; A magnetic device using a magnetic semiconductor, comprising: a magnetic head for writing or reading information from the recording area.

[0007] Further, the above-mentioned problem is solved by a magnetic semiconductor layer,
A plurality of first gate electrodes disposed on the magnetic semiconductor layer to divide the magnetic semiconductor layer into a plurality of recording areas;
A method for transferring magnetic information of a magnetic device having a second gate electrode formed on each recording area, wherein the plurality of second gate electrodes are applied with a voltage applied to each first gate electrode. A voltage is applied to a specific second gate electrode to erase magnetic information recorded in a recording area below the second gate electrode, and the first first gate electrode adjacent to the specific second gate electrode is erased. By stopping the application of the voltage to the gate electrode, the magnetic information recorded in the recording area below the second gate electrode adjacent to the specific second gate electrode with the first gate electrode interposed therebetween is recorded. The magnetic information copied below the first gate electrode is copied below the first gate electrode, the application of voltage to the specific second gate electrode is stopped, and the magnetic information copied below the first gate electrode is copied to the specific second gate electrode. Copy to the recording area below the electrode, stop applying voltage Be solved by the method of transferring magnetic information, characterized in that to erase the magnetic information below said first gate electrode to start a voltage applied to the first gate electrode.

Hereinafter, the operation of the present invention will be described. For example, a magnetic semiconductor is formed by doping a III-V compound semiconductor with a magnetic impurity such as Cr (chromium), Mn (manganese), or V (vanadium) (Ohno et al., "III-V Group Compound Semiconductor. Dilute Magnetic Semiconductor as a Base ", Solid State Physics, Vol.28, No.5 1993, Ohno et al.," Transport Phenomena and Magnetism of III-V Group Dilute Magnetic Semiconductors ", Applied Physics, Vol.
1994).

Also, for example, a magnetic semiconductor formed by doping a compound semiconductor such as InAs with a magnetic impurity such as Mn exhibits ferromagnetic properties due to the interaction between magnetic ions caused by carriers. On the other hand, if the number of carriers is small, the interaction between magnetic ions is weakened, and the magnetic ions exhibit paramagnetic properties. 1 and 2 are schematic diagrams showing the properties of a magnetic semiconductor. 1 and 2, arrows surrounded by circles indicate the directions of magnetic moments in the magnetic semiconductor layer.
The double arrow indicates the interaction between the magnetic ions. FIG.
As shown in (a), when no voltage is applied to the gate electrode 2 formed on the magnetic semiconductor layer 1, the carrier concentration in the magnetic semiconductor layer 1 is high, and the mutual between magnetic ions due to the carrier is high. With the action, the magnetic semiconductor layer 1 exhibits ferromagnetism. At this time, the magnetization curve of the magnetic semiconductor layer 1 is as shown in FIG.
The shape having hysteresis is obtained as shown in FIG.
Further, as shown in FIG. 2A, when a voltage is applied to the gate electrode 2, the carrier concentration of the magnetic semiconductor layer 2 below the gate electrode 2 is reduced, and the interaction between magnetic ions is reduced. The semiconductor layer 2 always shows. At this time, the magnetization curve of the magnetic semiconductor layer 2 below the gate electrode 1 is shown in FIG.
It becomes a straight line as shown in FIG.

In the present invention, recording, reproduction and transfer of magnetic information are performed utilizing the above-mentioned properties of the magnetic semiconductor.
That is, in the present invention, a first gate electrode for dividing the magnetic semiconductor layer into a plurality of recording areas is arranged on the magnetic semiconductor layer, and each recording gate divided by the first gate electrode is disposed. A second gate electrode is provided over the region.

When no voltage is applied to the second gate electrode, the magnetic semiconductor layer (recording region) below the second gate electrode shows ferromagnetism. Using the head, information can be magnetically recorded, and the recorded information can be reproduced. Further, information recorded in the recording area can be transferred between the recording areas by controlling the voltage applied to the first and second gate electrodes as described in an embodiment described later. Therefore, a large amount of information can be recorded on the recording medium without mechanically moving the recording medium.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 3 is a top view showing a magnetic device (magnetic recording device) using a magnetic semiconductor according to an embodiment of the present invention, FIG. 4 is a sectional view taken along line AA of FIG. 3, and FIG. 5 is BB of FIG. It is sectional drawing by a line. However,
3 and 4, the illustration of the magnetic head 20 shown in FIG. 5 is omitted. FIG. 6 is a top view showing the entire magnetic disk.

The magnetic disk 10 includes a substrate 11, a magnetic semiconductor layer 12 formed on the substrate 11, a plurality of first gate electrodes 13 formed radially on the magnetic semiconductor layer 12, And a second gate electrode 14 disposed between one gate electrode 13. The first gate electrode 13 and the second gate electrode 14 are connected to a voltage application unit (not shown), and a voltage is selectively applied from the voltage application unit.

For example, the substrate 11 is made of GaAs, the magnetic semiconductor layer 12 is made of In _0.82 Mn _0.18 As, and its thickness is about 100 nm. Also, the first gate electrode 1
The third and second gate electrodes 14 are made of aluminum,
The width is about 100 nm and the thickness is about 100 nm. Also,
The distance between the first gate electrodes 13 is smaller than the size of the magnetic domain of the magnetic semiconductor, and is set to, for example, 0.2 to 0.3 μm. Thereby, one information can be recorded in one magnetic domain, and the recording density can be increased.

A portion of the magnetic semiconductor layer 12 below each second gate electrode 14 is a recording area for recording information. In the present embodiment, as will be described later, one of a plurality of recording areas is used as a redundant area, and magnetic information is transferred by copying magnetic information in a recording area adjacent to the redundant area. On the other hand, the magnetic head 20
It comprises a supporting substrate 21 and a reproducing head 31 and a recording head 32 arranged on the side surface of the supporting substrate 21. The reproducing head 31 is formed with a lower magnetic shield layer 22 formed on the side surface of the substrate 21 via an alumina layer (not shown), and on the lower magnetic shield layer 22 with an alumina layer (not shown). MR element 23, an extraction electrode (lead terminal) 24 drawn from the MR element 23, an alumina layer 25 covering the MR element 23 and the extraction electrode 24, and a cover layer (not shown) on the alumina layer 25. ) And the upper magnetic shield layer 26 formed therebetween. The recording head 32 includes an upper magnetic shield layer 26, a third magnetic shield layer 27,
The coil 2 formed between the upper magnetic shield layer 26 and the third magnetic shield layer 27 via an insulating layer 28
9.

Then, the magnetic head 20 is moved on a specific second gate electrode 14 in the radial direction of the magnetic disk 10 by a driving device (not shown). Instead of moving the magnetic head, for example, a plurality of magnetic heads may be arranged on the magnetic disk 10 in the radial direction. Hereinafter, the operation of the information recording apparatus of the present embodiment will be described. First, the operation of moving the magnetic information recorded on the magnetic disk 10 in the circumferential direction will be described with reference to the schematic diagrams of the magnetic disk shown in FIGS. However, in these figures, circles surrounding the dots indicate the magnetic semiconductor layer 1.
2 indicates a magnetic field in an upward direction, and a circle surrounded by a circle indicates a magnetic field in a downward direction from the magnetic semiconductor layer 12.
The gate electrode 1 is located below the second gate electrode 14.
It is assumed that magnetic information is recorded at intervals such that the magnetic ions do not interfere with each other along the direction in which 4 extends. 7 to 9, five electrodes (13a, 13b, 13c, 13d, 13e) of the first electrode 13 and the second electrode 13
Of the four electrodes 14 (14a, 14b, 14
c, 14d). Then, in the initial state, the magnetic semiconductor layer 12 below the magnetic semiconductor layer 12 below the second electrode 14b is a redundant region, and the recording is performed below the second electrode 14b below the second electrode 14a. It is assumed that the same magnetic information is recorded.

In the initial state, as shown in FIG.
Each of the first gate electrodes 13a to 13
A voltage of about 1 V is applied to e, and no voltage is applied to each of the second gate electrodes 14a to 14d. For this reason, the first gate electrodes 13 a to 13 of the magnetic semiconductor layer 12 are formed.
The portion below e has a small number of carriers (holes) and exhibits a constant state, and the portion below the second gate electrodes 14a to 14d exhibits a magnetic moment in a certain direction due to the carriers and exhibits ferromagnetism. Magnetic information is recorded in each recording area.

First, the magnetic information in the redundant area is erased. That is, as shown in FIG. 7B, the second gate electrode 1
A voltage of about 1 V is applied to 4b. Then, carriers (holes) in the magnetic semiconductor layer 12 below the second gate electrode 14b are reduced, and the direction of the magnetic moment becomes random. Thereby, the magnetic information in the redundant area below the second gate electrode 14b is erased.

Next, as shown in FIG. 8A, the application of the voltage to the first gate electrode 13c adjacent to the second gate electrode 14b is stopped. Thereby, the first gate electrode 1
The magnetic semiconductor layer 12 below 3c always shows sexual behavior,
Under the influence of the ferromagnetism of the magnetic semiconductor layer 12 below the second gate electrode 14c, the direction of the magnetic moment of the magnetic semiconductor layer 14c below the second gate electrode 14c becomes the same. That is, the magnetic information in the recording area below the second gate electrode 14c is copied to the recording area below the first gate electrode 13c.

Next, as shown in FIG. 8B, the application of the voltage to the second gate electrode 14b is stopped. This allows
The magnetic semiconductor layer 12 below the second gate electrode 14b exhibits ferromagnetic behavior, and magnetic information below the first gate electrode 13c is transferred to the magnetic semiconductor layer 1 below the second gate electrode 14b.
2 is copied. Next, as shown in FIG. 9, a voltage is applied to the first gate electrode 13c. As a result, the magnetic semiconductor layer 12 below the first gate electrode 13c becomes permanent and magnetic information is erased.

As described above, the second gate insulating layer 14
c is transferred to the second gate electrode 14
b can be transferred below. After that, magnetic information recorded below the second gate electrode 14d is transferred to a recording area below the second gate electrode 14c, with the area below the second gate electrode 14c as a redundant area. In this manner, the magnetic information recorded on the magnetic disk 10 can be sequentially moved to the next recording area.

Next, an operation for recording information in the recording area and reading information recorded in the recording area will be described. The magnetic head 20 moves on a specific second gate electrode 14. Then, a magnetic field corresponding to the current supplied to the coil 29 is generated, and information is recorded by magnetizing the magnetic semiconductor layer 12. Magnetic information recorded in the magnetic semiconductor layer 12 moves to an adjacent recording area by selectively applying a voltage to the first gate electrode 13 and the second gate electrode 14 by the voltage applying unit 17. Thereafter, the specific second gate electrode 14 is
The information is recorded in the recording area below. In this way,
A large amount of information can be recorded on a magnetic disk.

On the other hand, when reading information from the magnetic disk, the fact that the resistance value of the MR element 23 of the magnetic head 20 changes due to the magnetic field emitted from the recording area is used.
Read information. After that, the voltage applied to the first and second gate electrodes is controlled by the voltage application unit 17, and the information recorded in the next recording area is read by moving it below the magnetic head 20.

As described above, in this embodiment, a large amount of information can be recorded on the magnetic disk, and the information recorded on the magnetic disk can be easily read. In this case, the magnetic recording apparatus according to the present embodiment does not need to rotate the magnetic disk, so that the recording apparatus can be made compact and power consumption can be reduced.

It should be noted that the magnetic device of the present invention comprises first and second magnetic devices.
The information recorded on the magnetic semiconductor layer can be sequentially moved only by controlling the voltage applied to the gate electrode, so that it not only functions as recording and reproducing information but also functions as a shift register, a digital delay element, and the like. Can be. Further, in the above-described embodiment, the case where the recording medium is formed in a disk shape and the information is rotated in one direction has been described. However, the shape of the recording medium is not limited to the disk shape. The information may be moved in the opposite direction.

Further, in the above embodiment, the magnetic semiconductor layer
Although the case of nMnAs has been described, as a material of the magnetic semiconductor layer, other than this, a magnetic semiconductor formed by doping Mn into GaAs or a II-VI group compound semiconductor such as CdTe doped with Mn is formed. Magnetic semiconductors and the like can be used.

[0027]

As described above, according to the present invention,
By selectively applying a voltage to the first and second gate electrodes formed on the magnetic semiconductor layer, information recorded in one recording area can be moved to another recording area. As a result, a magnetic recording device that does not require the rotation of the disk is made possible, and the size of the magnetic recording device can be reduced and the power consumption can be reduced. Further, according to the present invention, the information recorded in the recording area can be moved by controlling the voltage applied to the first and second gate electrodes, so that it can be applied to a shift register, a delay element, and the like. Is also possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing properties of a magnetic semiconductor, showing a state where no voltage is applied to a gate electrode.

FIG. 2 is a schematic diagram showing properties of a magnetic semiconductor, showing a state where a voltage is applied to a gate electrode.

FIG. 3 is a top view showing an information recording device using a magnetic semiconductor according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a top view showing a magnetic disk.

FIG. 7 is a diagram (part 1) illustrating an operation of the information recording apparatus of the embodiment.

FIG. 8 is a diagram (part 2) illustrating an operation of the information recording apparatus of the embodiment.

FIG. 9 is a diagram (part 3) illustrating an operation of the information recording apparatus of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 12 Magnetic semiconductor layer 2 Gate electrode 10 Magnetic disk 11 Substrate 13 First gate electrode 14 Second gate electrode 20 Magnetic head 21 Support substrate 22, 26, 27 Magnetic shield layer 23 MR element 29 Coil 31 Reproduction head 32 Recording head

Claims (5)

[Claims] 1. A magnetic semiconductor layer; a plurality of first gate electrodes disposed on the magnetic semiconductor layer to divide the magnetic semiconductor layer into a plurality of recording areas; A magnetic device using a magnetic semiconductor, comprising: a second gate electrode. 2. A substrate, a magnetic semiconductor layer formed on the substrate, a first gate electrode formed on the magnetic semiconductor layer to divide the magnetic semiconductor layer into a plurality of recording areas, A second gate electrode formed on the area, voltage applying means for selectively applying a voltage to the first gate electrode and the second gate electrode, and writing information in the recording area or the recording area A magnetic device using a magnetic semiconductor, comprising: a magnetic head that reads information from a magnetic head. 3. The magnetic semiconductor layer is made of InMnAs, G
3. The method according to claim 1, wherein the material is any one selected from the group consisting of aMnAs and CdMnTe.
A magnetic device according to claim 1. 4. The magnetic recording medium according to claim 1, wherein the recording area is smaller than a magnetic domain of the magnetic semiconductor.
A magnetic device using the magnetic semiconductor according to 1. 5. A magnetic semiconductor layer, a plurality of first gate electrodes disposed on the magnetic semiconductor layer and dividing the magnetic semiconductor layer into a plurality of recording areas, and formed on each recording area. A method of transferring magnetic information of a magnetic device having a second gate electrode, wherein a specific second gate of the plurality of second gate electrodes is applied while a voltage is applied to each first gate electrode. A voltage is applied to the electrode to erase magnetic information recorded in a recording area below the second gate electrode, and the application of a voltage to the first gate electrode adjacent to the specific second gate electrode is stopped. By doing so, the magnetic information recorded in the recording area below the second gate electrode adjacent to the specific second gate electrode with the first gate electrode interposed therebetween is written below the first gate electrode. Copying, voltage to said specific second gate electrode Stopping the application and copying the magnetic information copied below the first gate electrode to a recording area below the specific second gate electrode, and applying a voltage to the first gate electrode where the voltage application is stopped. A method for transferring magnetic information, comprising: starting application and erasing magnetic information below the first gate electrode.