JP2614246B2 - Bloch line memory writing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a writing method for a Bloch line memory,
More specifically, the present invention relates to a Bloch line memory writing method in which information (Bloch line pairs) is injected into a stripe domain domain wall at high speed using a photo-induced magnetized substance.

[Prior Art] With the development of high-density storage elements, Bloch line memories have attracted close attention because of their enormous storage capacity and non-volatility.

In the Bloch line memory, an information storage section is configured by a domain wall around a stripe domain in which a bulb domain is elongated, and information is recorded in the presence or absence of a Bloch line pair. The Bloch line memory (Bloch line memory device) is roughly composed of three elements: (i) a writing unit, (ii) a recording and transferring unit, and (iii) a reading unit.

Conventionally, information is written in the following order: generation of magnetic bubbles, transfer of bubbles to the end of a recording transfer section (stripe domain), application of a local magnetic field, and Bloch line writing corresponding to the presence or absence of bubbles. Have been.

However, such a conventional Bloch line memory writing method has problems that a long writing time is required, the configuration of the device itself tends to be complicated, and many manufacturing steps are required.

[Purpose] The present invention provides a method capable of simplifying a writing unit and writing data in a Bloch line memory at high speed.

[Configuration] In the Bloch line memory writing method of the present invention, a photo-induced magnetized substance is arranged adjacent to a stripe domain end,
The method is characterized in that Bloch lines are formed in the stripe domains by irradiating the light-induced magnetized material with circularly polarized laser light. Also, a photo-induced magnetized material is arranged near the edge of the stripe domain, and a Bloch line writing conductor is arranged between the stripe domain and the photo-induced magnetized material. Irradiating circularly polarized light to form a Bloch line in the stripe domain.

Incidentally, the inventors of the present invention have conducted intensive studies and studies on writing in a Bloch line memory, and as a result, have confirmed that the photo-induced magnetization effect can be used for writing. The method of the present invention has been made based on this. It is known that the photo-induced magnetization effect is applied to recording on a magneto-optical recording medium or used for driving a bubble domain (Japanese Patent Laid-Open No. 57-60504). There is no example in which the effect is applied to writing in a Bloch line memory.

Hereinafter, the method of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 and FIG. 2 are schematic diagrams of a writing section of two examples of Bloch line memory devices used in the method of the present invention;
11 is a substrate, 12 is a magnetic film, 13 is a stripe domain, 14 is a Bloch line writing conductor, and 15 is a photo-induced magnetized substance. In the example of FIG. 1, a mobile phone is used in which the photo-induced magnetized substance 15 is arranged adjacent to (in contact with) the end of the stripe domain 13, and a Bloch line writing conductor is provided here. Not. In the example of FIG. 2, the light-induced magnetized substance 15 is arranged close to the end of the stripe domain 13 (a distance d = about 10 to 100 μm), and the end of the stripe domain 13 and the light-induced magnetization A form in which a Bloch line writing conductor 14 is disposed between the substance 15 and the substance 15 is adopted.

The substrate 11 includes gadolinium, gallium, garnet (GG
G) is used. Then, a magnetic film 12 having a stripe domain 13 is formed on the substrate 11 by a thin film forming technique such as the LPE method. At this time, processing such as grooving formation and formation of a high coercive force film may be employed to stabilize the stripe domain 13.

A light-induced magnetizable substance 15 is located adjacent to or at some distance from (at close to) the end of the stripe domain 13. Means a substance that can control the magnitude and direction of its magnetization. A typical example of the light-induced magnetized substance 15 is a ruby single crystal (Al ₂ O ₃ : Cr). The light-induced magnetized substance 15 is formed on the magnetic film 12 by a thin film forming method such as a sputtering method or an LPE method. It is made into a thin film by applying technology.

Writing (recording) of the Bloch line memory in the method of the present invention is performed by irradiating the photo-induced magnetized substance 15 with circularly polarized light. FIG. 3 schematically shows this writing.

First, writing to the device shown in FIG. 1 will be described. As seen in FIG. 3, the light source
The laser light from 21 is irradiated through the lens 22, the polarizer 23, and the optical modulator 24 to the thin-film photo-induced magnetized substance 15 adjacent to the end of the stripe domain 13. It is desirable to use a ruby laser as the light source 21. In FIG. 3, reference numeral 1 denotes a Bloch line memory device.

The coherent light emitted from the light source 21 is converged by the lens 22 and becomes linearly polarized light through the polarizer 23. The light modulator 24 modulates the linearly polarized light into left and right circularly polarized light in accordance with a voltage (not shown) from a modulation signal source. The ruby single crystal 15 is irradiated sequentially.

Since magnetizations having different polarities are generated from the light-induced magnetized substance 15 depending on the rotation direction (left and right) of the circularly polarized light, if the presence or absence of a signal is converted to the rotation direction of the circularly polarized light, a magnetic field having a different direction can be obtained. A Bloch line pair is formed in the stripe domain 13 according to the presence or absence of a signal.

On the other hand, in the device shown in FIG. 2, when a magnetic field is generated by irradiating the photo-induced magnetized substance 15 with circularly polarized light in the same manner as described above, the end of the stripe domain 13 expands and contracts in accordance with the magnetic field. At this time, the rotation direction of the circularly polarized light is fixed to either the clockwise direction or the counterclockwise direction so that the edge of the stripe domain extends.

Therefore, since the stripe domain 13 extends to the Bloch line writing conductor 14 when irradiating circularly polarized light, a Bloch line pair is formed at the end of the stripe domain 13 by applying a current to the conductor 14 so as to synchronize with the circularly polarized light irradiation. Is done.

 Next, examples will be described.

Example 1 According to the method described above, a garnet film having a thickness of 2 to 3 μm was formed on a gadolinium gallium garnet substrate (GGG substrate), and a transfer pattern of a stripe domain was formed thereon by ion implantation. Also, a Bloch line memory device of the type shown in FIG. 1 was fabricated by forming a ruby single crystal film having a thickness of 100 to 110 μm by LPE so as to be in contact with the end of the stripe domain.

Subsequently, when writing was performed on this device by the means described with reference to FIG. 3, a signal writing portion was obtained with a very simple configuration, and recording consisting of a Bloch line pair was performed in the stripe domain.

Example 2 A garnet film was formed on a GGG plate in the same manner as in Example 1,
A stripe domain is formed thereon, and 100 to 110 μm at a distance of about 20 μm from the end of the stripe domain.
A thick ruby single crystal film was formed. Further, a Bloch line writing conductor (Al vapor deposited film) having a thickness of about 0.6 μm was provided between the end of the stripe domain and the ruby single crystal film to produce a Bloch line memory device of the type shown in FIG.

Subsequently, when the device was written by the means described with reference to FIG. 3, the magnetization generation of the photo-induced magnetized material was used only to extend the edge of the stripe domain, and the accuracy of the magnetization generation was reduced. Rough settings were made, and a record consisting of a pair of Bloch lines was recorded in the stripe domain.

[Effect] According to the method of the present invention, the configuration of the device is simplified, and in addition, the speed of signal writing is increased.

[Brief description of the drawings]

1 and 2 are schematic diagrams of two examples of a writing section of a Bloch line memory device used in the method of the present invention.
FIG. 3 is a diagram for explaining means for writing signals to these devices. DESCRIPTION OF SYMBOLS 1 ... Bloch line memory device 11 ... Substrate, 12 ... Magnetic film 13 ... Stripe domain 14 ... Bloch line writing conductor 15 ... Photoinduced magnetized substance, 21 ... Light source 22 ... Lens, 23 ... Polarizer 24 …… Light modulator

Claims (2)

(57) [Claims] 1. A photo-induced magnetizable material is arranged adjacent to an end of a stripe domain, and a Bloch line is formed in the stripe domain by irradiating the photo-induced magnetic material with circularly polarized laser light. Bloch line memory writing method. 2. A photo-induced magnetizable material is disposed adjacent to an end of a stripe domain, and a Bloch line writing conductor is disposed between the stripe domain and the photo-induced magnetic material. Irradiating circularly polarized light of a laser beam on the stripe domain to form a Bloch line in the stripe domain.