JPH0668665A - Bloch line memory element and memory device using this element - Google Patents

Abstract

PURPOSE:To shorten access time by forming a magneto-optical film on a ferromagnetic material thin film having an information input/output function part for making cross-exchange of a Bloch line pair and bubble magnetic domains and executing writing/reading out by using a laser beam. CONSTITUTION:The surface of the ferromagnetic material thin film 15 of the Bloch line element is provided with the magnetooptical film 13 consisting of a TbFeCo alloy film or multilayered CoPt films, etc. The writing of the information is executed by previously impressing bias magnetic fields to the element, irradiating the film 13 with the laser 23 to write the magnetic domains 18 in correspondence to the upper part within the film 13, then writing the Bloch line pairs within the striped magnetic domains 1 by a magnetostatic effect. The reading out of the information is executed by lowering the coercive force of the film 13 by irradiation of the film with the laser, thereby converting the magnetic domain arrays in the magnetic domains 1 to the magnetic domain array in the film 13, then detecting the light as reflected light. Then, the Bloch line memory is constituted without using fine zigzag conductor patterns and the access time is shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid magnetic memory device, and more particularly to a Bloch line memory device suitable for realizing a large capacity file memory and a memory device using the same.

[0002]

2. Description of the Related Art Regarding Bloch line memory devices,
Japanese Patent Laid-Open No. 59-101092 describes a basic memory configuration. In this Bloch line memory element, the presence / absence of Bloch line pairs existing in the domain wall of the stripe magnetic domain arranged in the ferromagnetic material having the easy axis as the direction perpendicular to the film surface is determined by the information "1", "0". It is stored in correspondence with "". For information writing and reading operations in Bloch line memory devices, iE, E, Transaction on Magnetics, MSA 22, No. 5 (198).
6 years) 784 to 789 [IEEE Trans. On Mag
netics, MAG-22, No.5, (1986) pp784-pp789]]. In the information writing operation, "1" and "0" of information are associated with the presence or absence of bubble magnetic domains, the bubble magnetic domain row is transferred to the input / output function unit, and the stripe magnetic domain storing the bubble magnetic domain and the Bloch line pair is stored. It is an operation of writing a Bloch line pair corresponding to information "1" and "0" in the stripe magnetic domain by utilizing the magnetostatic interaction with. Information read operation is performed by converting the presence or absence of Bloch line at the end of the stripe magnetic domain into the presence or absence of bubble magnetic domain in the input / output function unit, transferring the converted bubble magnetic domain sequence to the magnetic domain detection unit, and utilizing the magnetoresistive effect. It is an operation of reading out as an electric signal.

[0003]

The above-mentioned prior art has the following two problems. First, 2
In a Bloch line memory device with a high storage density of 56 Mb / cm ² or more, the diameter of the bubble magnetic domain is 1 μm or less,
The problem is that the meandering conductor pattern that generates a magnetic field for transferring it must be miniaturized. That is, since a current of several tens mA is required to generate a magnetic field, there arises a problem that the withstand voltage of the conductor pattern is reduced due to the miniaturization of the meandering conductor pattern. Secondly, since the conversion speed of the magnetoresistive effect element that converts the presence or absence of bubble magnetic domains into an electric signal at the time of reading information cannot be increased to 200 kHz or more, there is a problem that the information access time becomes long.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to write and read information without using bubble magnetic domain arrays corresponding to "1" and "0" of information. To provide a Bloch line memory without using a fine meandering conductor pattern, and to provide a Bloch line memory device having a structure suitable for shortening information access time and a memory device using the same. It is in.

[0005]

In order to achieve the above object of the present invention, a ferromagnetic thin film having a direction perpendicular to the film surface as an easy axis of magnetization is arranged in a predetermined shape such as parallel or radial. In a Bloch line memory device using a Bloch line pair existing in a domain wall of a striped magnetic domain as an information carrier, on the above-mentioned ferromagnetic thin film having an information input / output function unit for performing mutual conversion between the Bloch line pair and the bubble magnetic domain. A magneto-optical film is formed on the optical disk, and information writing and reading operations are performed through a magnetic domain array generated in the magneto-optical film by using laser light.

According to the present invention, a Bloch line pair present in a magnetic domain wall of a stripe magnetic domain arranged in a predetermined shape is used as an information carrier in a ferromagnetic thin film having an axis of easy magnetization perpendicular to the film surface. In the Bloch line memory element, a Bloch line memory element is provided in which a magneto-optical film is provided on the ferromagnetic thin film having an information input / output function section for performing mutual conversion between a Bloch line pair and a bubble magnetic domain. The magneto-optical film is
It is preferable to use a TbFeCo alloy film or a CoPt multi-layer film, and multiple reflection of light is performed on the magneto-optical film.
And an enhancement film formed of at least one transparent thin film selected from a silicon nitride film such as SiN or a silicon oxide film such as SiO or SiO ₂ for increasing the polarization angle (Kerr rotation angle) of light. Is. Further, in the Bloch line memory element of the present invention, a conductor layer is formed under the magneto-optical film to form a Bloch line memory element.

The present invention constitutes a Bloch line memory device using the Bloch line memory device described above, and has a ferromagnetic material having an information input / output function unit for performing mutual conversion between a Bloch line pair and a bubble magnetic domain. Laser light generation means for irradiating a laser beam on the magneto-optical film provided on the thin film, means for scanning the laser beam on the magneto-optical film, and means for detecting reflected light from the magneto-optical film. It is at least a Bloch line memory device. The Bloch line memory device of the present invention, when writing information, irradiates a predetermined region on the magneto-optical film with laser light, and lowers the coercive force of the magneto-optical film in the irradiation region of the laser light, thereby Means for writing magnetic domains in the magneto-optical film corresponding to "1" and "0" is provided. In addition, the Bloch line memory device of the present invention includes a magnetic domain written in the magneto-optical film,
A means for writing a Bloch line pair in the stripe magnetic domain corresponding to information "1" or "0" by magnetostatic interaction with the stripe magnetic domain storing the Bloch line pair in the ferromagnetic thin film is provided. It is a thing. Further, in the Bloch line memory device of the present invention, at the time of reading information, the bubble magnetic domain array in the ferromagnetic thin film under the magneto-optical film converted in accordance with the presence or absence of the Bloch line pair is converted into a laser beam on the magneto-optical film. Means for reducing the coercive force of the magneto-optical film to convert it into a magnetic domain array in the magneto-optical film, and detecting the magnetic domain array in the magneto-optical film as reflected light when the laser beam is irradiated. It is equipped with.

[0008]

Since the conventional information writing operation in the Bloch line memory device is performed by utilizing the magnetostatic interaction between the bubble magnetic domain row and the stripe magnetic domain storing the Bloch line pair, the information is written in place of the bubble magnetic domain. Even when using the magnetic domain array generated in the magneto-optical film formed in the input / output part of
By using the magnetostatic interaction between the magnetic domain array and the stripe magnetic domain, it becomes possible to perform the information writing operation by the same operation as that in the case of using the bubble magnetic domain. Writing a magnetic domain in the magneto-optical film is performed by applying a current to the conductor below the magneto-optical film to generate a magnetic field in the direction opposite to the magnetization direction in the magneto-optical film, and then applying laser light to the location where the magnetic domain is generated. Irradiate
This can be done by lowering the coercive force of that portion. Therefore, generate a bubble magnetic domain sequence in another place,
It is not necessary to transfer it, and a fine meandering conductor pattern for transfer is unnecessary. In the information read operation, the presence / absence of Bloch line at the end of the stripe magnetic domain is first converted into the presence / absence of bubble magnetic domain so that the converted bubble magnetic domain exists under the magneto-optical film. Then, the magneto-optical film is magnetized in advance in the same direction as the magnetization direction of the bubble magnetic domain, and the coercive force is reduced by irradiating the magneto-optical film with a laser beam to reduce the coercive force of the magneto-optical film. Since the magnetization direction and the direction of the leakage magnetic field from the bubble magnetic domain are the same, the magnetization does not reverse, and in the other regions, the magnetization reverses to the direction of the bias magnetic field applied from the outside opposite to the leakage magnetic field, A magnetic domain array corresponding to the bubble magnetic domain array is generated. That is, the bubble magnetic domain array is copied to the magnetic domain array in the magneto-optical film. Information can be read out by detecting a magnetic domain array in the magneto-optical film by using the Kerr effect with laser light. Therefore, it is not necessary to detect the bubble magnetic domain array by the magnetoresistive effect element, and the information access time can be significantly shortened.

[0009]

【Example】

<Embodiment 1> Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2 to 5 (a diagram showing a procedure for writing information) and FIGS. 6 to 10 (a procedure for reading information). Will be described with reference to FIG. FIG. 1 is a schematic diagram showing an example of the configuration of an information input / output unit of a Bloch line memory device. The striped magnetic domains 1 that store Bloch line pairs that are information carriers are made to exist in a ferromagnetic thin film (magnetic garnet film) 15 which is liquid-layer grown on a non-magnetic substrate 14. The magneto-optical film (TbFeCo
A film 13 is formed and an enhancement film (a silicon nitride film such as SiN or a silicon oxide film such as SiO or SiO ₂ ) 35 for enhancing the polarization effect (Kerr effect) of the light from the magneto-optical film 13 is formed thereon (not shown). Form). At the time of writing a pair of Bloch lines, the light oscillated from the semiconductor laser 23 passes through the polarizer 25, the optical deflector 26, and the condenser lens 27, and is scanned by the optical deflector 26 on the magneto-optical film 13. The magnetic domain 18 is written in the contacted portion of the magneto-optical film. Magneto-optical film 1 corresponding to “1” and “0” of information
Utilizing the magnetostatic interaction between the magnetic domain 18 written in 3 and the striped magnetic domain 1, the presence or absence of the magnetic domain 18 is converted into the presence or absence of the Bloch line pair, and written in the striped magnetic domain 1. At the time of reading the Bloch line, the presence or absence of the Bloch line at the end of the stripe magnetic domain 1 is converted into the presence or absence of the bubble magnetic domain, and the magneto-optical film 13 is irradiated with a laser beam to reduce the coercive force thereof, so that the bubble magnetic domain array is formed. Magneto-optical film 13
It was copied to the row of magnetic domains 18 inside. In order to detect the array of magnetic domains 18 in the magneto-optical film 13, laser light having a power weaker than that at the time of writing was emitted from the semiconductor laser 23. The oscillated light includes a polarizer 25, a light deflector 26, and a condenser lens 27.
Is irradiated onto the magneto-optical film 13 via the optical deflector 26 and
Scanned by. Due to the Kerr effect, the degree of polarization of light (reflected light) is different between where the magnetic domain 18 is present and where it is not. However, since the effect of polarization is small in one reflection, the polarization effect was strengthened by reflecting the light multiple times on the magneto-optical film 13 by the enhance film 35. The reflected light passes through the half mirror 29, the analyzer 30, and the condenser lens 31.
The information was read by passing through the photodetector 32 and entering the photodetector 32 and detecting the intensity of the light.

Next, the configuration of the Bloch line memory device,
Also, information writing and reading operations in the Bloch line memory device will be described. First, the Bloch line memory device configuration will be described. Figure 2 (a)
2A is a schematic diagram showing the configuration of a functional portion of a Bloch line memory device, and FIG. 2B is a diagram showing a cross-sectional structure taken along line AA in FIG. 2A. Stripe domain 1
Is a ferromagnetic thin film 15 made of a GdGa-based magnetic garnet film having a thickness of about 1 μm grown on a non-magnetic substrate 14 made of gadolinium (Gd) gallium (Ga) garnet having a thickness of 0.4 mm. It existed inside and was fixed around the stripe magnetic domain fixing pattern 5. In this material, the width of the stripe magnetic domain 1 is about 1 μm, and
A storage density of Mb / cm ² can be realized. The guide pattern 6 plays the role of a guide when the stripe magnetic domain 1 is stretched when writing and reading information. The guard pattern 7 prevents unwanted magnetic domains from entering the functional portion from the outside. The stripe magnetic domain fixing pattern 5, the guide pattern 6, and the guard pattern 7 described above.
Is a groove pattern in which a ferromagnetic thin film (magnetic garnet film) 15 is dug. These patterns may be a ferromagnetic thin film having a high coercive force formed directly on the magnetic garnet film 15 or with a spacer interposed therebetween, and no problem occurred in carrying out the present invention. The conductor groups arranged above and below the functional portion of the Bloch line memory device indicate the information input / output conductor groups, and the write conductor 9 writes and reads (and erases) the Bloch line pair.
The conductor 10 is for reading and erasing the Bloch line, and the wide conductor 11 is for controlling the Bloch line at the time of input / output of information. The meandering conductor 12 is for generating an auxiliary bias magnetic field when writing a magnetic domain in the magneto-optical film 13. The write conductor 9, the read (and erase) conductor 10, and the meandering conductor 12 were formed on the magnetic garnet film 15 with the insulating layer 16 interposed therebetween. An insulating layer 17 is laminated thereon, and further,
A wide conductor 11 and a magneto-optical film 13 were formed on it. Figure 2
As is clear from (a), since the wide conductor 11 and the magneto-optical film 13 are formed in different regions, they are formed in the same layer. Then, an enhance film (SiN film) 35 for enhancing the polarization effect (Kerr effect) of the light from the magneto-optical film 13 was formed on the magneto-optical film 13. The Bloch line 3 existing in the domain wall 2 is a Bloch line pair 4 which is a carrier of information.
It is a dummy Bloch line to keep the stable. The bit pattern 8 is a bit positioning pattern for a Bloch line pair. The bit pattern 8 is a pattern formed by periodically changing the film thickness of the magnetic garnet film (ferromagnetic thin film) 15.

Next, the operation of writing information will be described with reference to FIGS.
This will be described with reference to FIG. At the time of writing, first, the magneto-optical film 13 is magnetized downward with respect to the film surface by an auxiliary bias magnetic field magnet (not shown) provided outside the memory element, and the current Ib is passed through the meandering conductor 12. Generated an upward magnetic field. After that, laser light was irradiated to the location where the magnetic domain was written corresponding to "1" and "0" of the information, and the coercive force of that portion was lowered. Then, the magnetization of the part where the coercive force is lowered is reversed to the upward magnetic field direction, and information "1",
A column of magnetic domains 18 corresponding to "0" is written in the magneto-optical film 13 [FIG. 2 (a)]. Next, the bias magnetic field applied to the entire Bloch line memory element was lowered, and the end of the stripe magnetic domain 1 was extended. At this time, due to the magnetostatic interaction with the magnetic domain 18 in the magneto-optical film 13, the stripe magnetic domain 1 in the portion where the magnetic domain 18 exists cannot be extended below the magneto-optical film 13 due to the repulsion by the magnetic domain 18. Only the striped magnetic domain 1 where there is no magnetic domain 18 extends below the magneto-optical film 13. Then, a Bloch line control current Ic was passed through the wide conductor 11 to hold the Bloch line 3 at the end of the stripe magnetic domain 1 on the side surface [FIG. 3]. Next, a write current Iw was passed through the write conductor 9 of the Bloch line pair, so that the Bloch line pair 19 was written only in the stripe magnetic domain 1 where there was no magnetic domain 18 (FIG. 4). By the above operation, the presence or absence of the magnetic domain 18 can be determined by the Bloch line pair
It was possible to write into the striped magnetic domain 1 after converting into the presence or absence of. After that, the bias magnetic field is returned to the original state, the coercive force is reduced by irradiating the magneto-optical film 13 with laser light, and the magnetic domain 18 is magnetized in one direction by an auxiliary bias magnetic field magnet provided outside the Bloch line memory element. It was erased [Fig. 5].

Next, the operation of reading information will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 6 is a schematic diagram showing a state before reading of the Bloch line memory element. Information "0" indicates that there is one Bloch line at the end of one stripe magnetic domain, and information "1" indicates that there are three Bloch lines.
Represents When reading, first, an auxiliary bias magnetic field magnet (not shown) provided outside the Bloch line memory element.
Thus, the magneto-optical film 13 was magnetized downward with respect to the film surface, the bias magnetic field was lowered, and the end portion of the stripe magnetic domain 1 was extended to below the magneto-optical film. At this time, the Bloch line control current Ic is applied to the wide conductor 11 to control the position of the Bloch line, and the Bloch lines 20, 21 and 22 are controlled.
At one end of the stripe magnetic domain where the book exists, three pieces are separated to make a state where one Bloch line 21 exists at the end of the stripe magnetic domain 1. Also, at the end of the stripe magnetic domain 1 where only one Bloch line 3 exists, the Bloch line 3
Was held on the side surface and a Bloch line was not formed at one end of the stripe magnetic domain [Fig. 7]. Here, the read (and erase) conductor 10 has a current I for cutting the magnetic domain of a desired value.
When r is applied, the striped magnetic domain 1 having the Bloch line at the end is cut off to generate a bubble magnetic domain 33, and the striped magnetic domain 1 having no Bloch line at the end is not cut off (FIG. 8). As described above, the presence or absence of the Bloch line pair can be converted into the presence or absence of the bubble magnetic domain 33. After that, the magneto-optical film 13 was irradiated with laser light to reduce the coercive force at that portion. Then, the portion without the bubble magnetic domain 33 was magnetized upward by the bias magnetic field, and the portion with the bubble magnetic domain 33 was magnetized downward by the downward leakage magnetic field from the bubble magnetic domain 33. That is, a row of magnetic domains 18 corresponding to the row of bubble magnetic domains 33 was generated in the magneto-optical film 13 [FIG. 9]. Information could be read out by detecting the row of the magnetic domains 18 with laser light by using the Kerr effect. After that, the magnetic domain erasing current Ia is applied to the meandering conductor 12.
Flowing to erase the bubble magnetic domain 33, and at the same time, the magneto-optical film 1
3 was irradiated with laser light to reduce the coercive force, and magnetized in one direction by an auxiliary bias magnetic field magnet provided outside the memory element to erase the magnetic domain 18 [FIG. 10]. According to the present embodiment, it becomes possible to perform the writing and reading operations of information without using the bubble magnetic domain row corresponding to the information "1" and "0", and the meandering conductor for bubble magnetic domain transfer is unnecessary. Becomes Further, it is not necessary to detect the bubble magnetic domain by the magnetoresistive effect element. Therefore, the Bloch line memory element can be constructed without using the fine meandering conductor pattern, and the information access time can be shortened significantly.

<Second Embodiment> A second embodiment of the present invention will be described below with reference to FIG. FIG. 11 is a schematic diagram showing an example of the configuration of the information input / output unit of the Bloch line memory device. The striped magnetic domains 1 for storing Bloch line pairs, which are information carriers, are radially arranged in a circular magnetic garnet film (ferromagnetic thin film) 15 grown on a circular non-magnetic substrate 14 in a liquid layer. A strip-shaped magneto-optical film (TbFeCo) is used for the information input / output function section of the innermost and outermost portions of the disk.
Film 13 is formed concentrically, and an enhancement film (a silicon nitride film such as SiN or SiO, SiO ₂ ) for enhancing the polarization effect (Kerr effect) of the light from the magneto-optical film 13 is formed thereon.
Silicon oxide film) was formed. At the time of writing the pair of Bloch lines, the light emitted from the semiconductor laser 23 was irradiated onto the magneto-optical film 13 via the polarizer 25, the optical deflector 26, and the condenser lens 27. Motor 34
The magnetic domain 18 is rotated by irradiating light to a position facing the end of the stripe magnetic domain 1 where information is written.
I wrote. The laser beam was tracked by the optical deflector 26 or mechanically only in the radial direction of the disc so that the spot 28 was located on the strip-shaped magneto-optical film 13 during the rotation of the disc. Information "1", "0"
Corresponding to, utilizing the magnetostatic interaction between the magnetic domain 18 written in the magneto-optical film 13 and the stripe magnetic domain 1,
The presence or absence of the magnetic domain 18 was converted into the presence or absence of the Bloch line pair, and writing was performed in the stripe magnetic domain 1. At the time of reading a Bloch line, the presence or absence of the Bloch line at the end of the stripe magnetic domain 1 is converted into the presence or absence of the bubble magnetic domain, and the magneto-optical film 13 is irradiated with laser light to lower the coercive force of that portion, thereby forming the bubble magnetic domain array. Was copied to the row of magnetic domains 18 in the magneto-optical film 13. In order to detect the array of magnetic domains 18 in the magneto-optical film 13, laser light having a power weaker than that at the time of writing was emitted from the semiconductor laser 23. The oscillated light is reflected by the polarizer 25,
Via the optical deflector 26 and the condenser lens 27, the magneto-optical film 1
Irradiated on top of 3. By rotating the disk by the motor 34, the band-shaped magneto-optical film 13 was scanned with laser light. Similar to the information writing operation, the spot 28 of the laser beam is just a strip-shaped magneto-optical film 1 while the disk is rotating.
Tracking was performed only by the optical deflector 26 or mechanically in the radial direction of the disk so as to be located on the third position. Due to the Kerr effect, a difference occurs in the degree of polarization of light (reflected light) in the presence or absence of the magnetic domain 18. Since the polarization effect is small in one reflection, the polarization effect is strengthened by reflecting the light multiple times on the magneto-optical film 13 by the enhance film 35. The reflected light passes through the half mirror 29, and the analyzer 3
0, information is read by passing the light through the condenser lens 31 and detecting the intensity of light by the photodetector 32.
According to the present embodiment, it becomes possible to perform the writing and reading operations of information without using the bubble magnetic domain row corresponding to the information "1" and "0", and the meandering conductor for bubble magnetic domain transfer is unnecessary. Becomes Further, it is not necessary to detect the bubble magnetic domain by the magnetoresistive effect element. Therefore, the Bloch line memory element can be constructed without using the fine meandering conductor pattern, and the information access time can be significantly shortened.

[0014]

According to the present invention, information "1", "0"
It becomes possible to perform information writing and reading operations without using the bubble magnetic domain array corresponding to, and the meandering conductor for bubble magnetic domain transfer becomes unnecessary. Further, it is not necessary to detect the bubble magnetic domain by the magnetoresistive effect element. Therefore, the Bloch line memory element can be configured without using a fine meandering conductor pattern, and the information access time can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a Bloch line memory device exemplified in a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a procedure of a write operation of information (Bloch line) exemplified in the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a procedure of an information writing operation exemplified in the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a procedure of an information writing operation illustrated in the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a procedure of an information writing operation exemplified in the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a procedure of an information read operation exemplified in the first embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a procedure of an information read operation illustrated in the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a procedure of an information read operation illustrated in the first embodiment of the present invention.

FIG. 9 is an explanatory diagram showing the procedure of the information read operation illustrated in the first embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a procedure of an information read operation exemplified in the first embodiment of the present invention.

FIG. 11 is a schematic diagram showing the configuration of the Bloch line memory device illustrated in the second embodiment of the present invention.

[Explanation of symbols]

1 ... Striped magnetic domain 2 ... Domain wall 3 ... Bloch line 4 ... Bloch line pair 5 ... Stripe magnetic domain fixing pattern 6 ... Guide pattern 7 ... Guard pattern 8 ... Bit pattern 9 ... Write conductor 10 ... Read (and erase) Conductor (two parallel conductors) 11 ... Wide conductor 12 ... Meandering conductor 13 ... Magneto-optical film (TbFeCo film) 14 ... Non-magnetic substrate 15 ... Ferromagnetic thin film (magnetic garnet film) 16 ... Insulating layer 17 ... Insulating layer 18 ... magnetic domain (magnetic domain in magneto-optical film) 19 ... Bloch line pair 20, 21, 22 ... Bloch line 23 ... semiconductor laser 24 ... condenser lens 25 ... polarizer 26 ... optical deflector 27 ... condenser lens 28 ... spot 29 ... Half mirror 30 ... Analyzer 31 ... Condenser lens 32 ... Photodetector 33 ... Bubble magnetic domain 34 ... Motor 35 ... Enhance film I ... write current Ic ... Bloch line control current Ir ... read current Ia ... domains erase current Ib ... magnetic field generating current

Claims (9)

[Claims] 1. A Bloch line using a pair of Bloch lines present in a domain wall of a stripe magnetic domain arranged in a predetermined shape as a carrier for information in a ferromagnetic thin film whose easy axis is a direction perpendicular to the film surface. In a memory device, a Bloch line memory device, wherein a magneto-optical film is formed on the ferromagnetic thin film having an information input / output function unit for performing mutual conversion between a Bloch line pair and a bubble magnetic domain. 2. The Bloch line memory device according to claim 1, wherein the magneto-optical film is a TbFeCo alloy film or Co.
A Bloch line memory device comprising a Pt multilayer film. 3. The Bloch line memory element according to claim 1 or 2, wherein an enhancement film that multiple-reflects light and increases a polarization angle of light is formed on the magneto-optical film. Bloch line memory device. 4. The Bloch line memory device according to claim 3, wherein the enhancement film is made of at least one transparent thin film selected from a silicon nitride film and a silicon oxide film. . 5. A Bloch line memory element according to claim 1, wherein a conductor layer is formed below the magneto-optical film. 6. A Bloch line memory device constituted by using the Bloch line memory element according to any one of claims 1 to 5, comprising: a laser beam generating means for irradiating a magneto-optical film; A Bloch line memory device comprising at least a means for scanning a laser beam on a magneto-optical film and a means for detecting a reflected light from the magneto-optical film. 7. A Bloch line memory device according to claim 6, wherein a predetermined region on the magneto-optical film is irradiated with laser light when writing information, and the coercive force of the magneto-optical film in the irradiation region of the laser light is increased. By lowering the information "1",
A Bloch line memory device comprising means for writing a magnetic domain in a magneto-optical film corresponding to "0". 8. The Bloch line memory device according to claim 6, wherein the magnetic domain written in the magneto-optical film and the stripe magnetic domain storing Bloch line pairs in the ferromagnetic thin film are magnetostatically interacted with each other. , A Bloch line memory device comprising means for writing Bloch line pairs in a stripe magnetic domain corresponding to information "1" and "0". 9. The Bloch line memory device according to claim 6, wherein when reading information, a bubble magnetic domain array in the ferromagnetic thin film under the magneto-optical film is converted according to the presence or absence of a Bloch line pair, When the laser beam is irradiated onto the magnetic film, the coercive force of the magneto-optical film is lowered to convert it into a magnetic domain array in the magneto-optical film, and the magnetic domain array in the magneto-optical film is irradiated with the laser beam. A Bloch line memory device comprising means for detecting reflected light.