JPS5811713B2 - Entoujiku Hatseiiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a generator of cylindrical magnetic domains for use in magnetic storage devices.

A crystal with uniaxial magnetic anisotropy such as rare earth orthoferrite or garnet is cut into flakes in a plane perpendicular to its axis, or a garnet thin film grown epitaxially is cut in the perpendicular direction, that is, in the direction of its easy magnetization axis. It is known that when a uniform magnetic field of an appropriate magnitude is applied, a so-called bubble domain, a cylindrical magnetic domain whose magnetization direction is opposite to that of the surrounding area, is created.

The most commonly used method for using this cylindrical magnetic domain as a memory element is to set information "1" when the cylindrical magnetic domain is present.
This is a method in which the time when there is no magnetic domain corresponds to information "0", and therefore a device or element is required that can freely generate cylindrical magnetic domains according to the information.

As shown in Fig. 1, the conventional and widely used method for generating cylindrical magnetic domains is to attach a cylindrical magnetic domain 2' as a seed to a disc-shaped soft magnetic material 1', and then apply it to a rotating magnetic field. This is a method in which a cylindrical magnetic domain serving as a seed is stretched and cut by rotating the Hr.

One of the drawbacks of this method is that the seed bubble makes one revolution around a relatively large disc-shaped pattern with respect to the rotation of the rotating magnetic field Hr, so it becomes increasingly difficult to follow the rotation as the rotational frequency of the rotating magnetic field Hr increases. This is at the point where it becomes impossible to generate cylindrical magnetic domains at high frequencies.

In order to eliminate this drawback, a method was developed that generates cylindrical magnetic domains by directly reversing magnetization, which is usually called a nucleation type generator.

An example of this is shown in FIG.

A ■-shaped pattern 3 is arranged between Y-pattern 1 and Y-pattern 2 of the YY-type drive pattern, and a hairpin-shaped conductor 4 is placed under this pattern.
A cylindrical magnetic domain generator is constructed by arranging the cylindrical magnetic domain generator.

A cylindrical magnetic domain is generated at position 5 by passing current through the hairpin-shaped conductor 4 such that the direction of the local vertical magnetic field at position 5 is opposite to the magnetization direction of the cylindrical domain material.

The minimum current value required to generate a cylindrical magnetic domain is
Although it varies depending on the magnitude of magnetization of the cylindrical domain material, the magnitude of magnetic anisotropy, the method of configuring the element, etc., according to experimental results, it is 300 to 400 mA for a normal garnet thin film.
It is.

Generating a cylindrical magnetic domain requires a fairly large current value as described above, and therefore, once generated, the cylindrical magnetic domain extends from position 5 to position 6 along the ■-shaped pattern 3.
A phenomenon is observed in which the movement margin to the next Y pattern decreases.

The object of the present invention is to change the shape of the hairpin-shaped conductor pattern so that it intersects with the Y-shaped pattern.
No matter how large the current value required to generate a cylindrical magnetic domain, it will not reduce the movement margin of the generated cylindrical magnetic domain.
An object of the present invention is to provide a cylindrical magnetic domain generator.

The principle of the present invention will be explained in detail with reference to examples.

FIG. 3 shows an embodiment of the invention relating to a cylindrical domain generator.

A type 1 pattern 3 is arranged between Y pattern 1 and Y pattern 2 of the YY type drive pattern, and a hairpin-shaped conductor 1 is placed under this pattern.
Place 4.

In this case, the hairpin-shaped conductor 14 is configured to intersect at the middle portion 9 of the Y-shaped pattern 3.

A current 40 is applied to the hairpin conductor 14 such that the local vertical direction at position 5 is opposite to the magnetization direction of the cylindrical domain material.
Flow 0mA.

The current is passed over the direction of the in-plane rotating magnetic field Hr between 20 and 21.

The local vertical magnetic field at position 5 is applied in a direction that expands the generated cylindrical magnetic domain, but at position 6, which is outside the hairpin-shaped conductor 14, it is applied in a direction that conversely contracts the cylindrical magnetic domain.

Therefore, the generated cylindrical magnetic domain does not expand over the entire Y-shaped pattern 3, and moves to the next Y-pattern without malfunction as the in-plane rotating magnetic field Hr rotates.

As a result, there is a significant increase in the driving margin.

The above has only shown one embodiment, and it goes without saying that the shape of the conductor pattern may be freely modified within the scope of the gist of the present invention.

[Brief explanation of the drawing]

Figure 1 shows a conventional disk-type cylindrical magnetic domain generator.
' is a thin film pattern made of soft magnetic material for holding the seed bubble 2', 3' is a pattern for moving the generated cylindrical magnetic domain, and the figure shows the state when the rotating magnetic field Hr is oriented in the direction of 10. shows. FIG. 2 shows a conventional nucleation type cylindrical magnetic domain generator, in which a Y-shaped pattern 3 is arranged between Y-shaped patterns 1 and 2, and at the same time, a hairpin-shaped conductor 4 is arranged so as to surround the entire 1-type pattern. ing. FIG. 3 shows an embodiment of the present invention, and shows a Y-shaped pattern and a Y-shaped pattern.
The arrangement of the mold patterns is the same as in FIG. 2, but the hairpin-shaped conductor patterns 14 are arranged so as to intersect at the midpoint 9 of the Y-shaped pattern.

Claims (1)

[Claims] 1. In a nucleation-type cylindrical magnetic domain generator composed of a hairpin-shaped conductor pattern and a soft magnetic material pattern, a part of the hairpin-shaped conductor pattern is arranged substantially parallel to the hairpin-shaped conductor pattern. A cylindrical magnetic domain generator characterized in that (1) is bent and arranged so as to enclose one end of a soft magnetic material pattern and not enclose the other end.