JPS58179986A - Magnetic bubble memory element - Google Patents

Abstract

PURPOSE:To obtain a memory element which has no deterioration of transfer characteristics owing to the bubble transfer direction, by setting the transfer direction of a clubfoot pattern to a prescribed direction in terms of the magnetic field facilitating axis and at the same time by applying an electrostatic magnetic field of a prescribed direction in order to increase the pattern gap margin. CONSTITUTION:The magnetic bubble transfer paths II and IV which are formed with clubfoot patterns of a large pattern gap margin are set in parallel and unparallel to an axis direction of easy magnetization (1, 1, -2). An electrostatic magnetic field is applied to the paths II and IV to form a holding magnetic field in the direction rectangular to the bubble transfer direction. Thus the transfer margin is increased. As a result, the margin of the pattern gap is increased and furthermore no deterioration of transfer characteristics owing to the bubble transfer direction is generated for a magnetic bubble memory element.

Description

DETAILED DESCRIPTION OF THE INVENTION (11) Technical Field of the Invention The present invention relates to a magnetic bubble memory element used as a memory for electronic computing devices or terminal devices thereof.

(2) Background of the technology Magnetic bubble utilization devices that use magnetic bubbles to store information, perform logical operations, etc. are nonvolatile, have high storage density, and low power consumption, and are solid-state devices that do not contain any mechanical elements. Therefore, it has many characteristics such as extremely high reliability of 1.2, and is expected to have a promising future as a large capacity memory.

This magnetic bubble memory device utilizes the fact that magnetic bubbles can be freely moved in an a-type thin film having uniaxial anisotropy by a magnetic field, and as shown in FIG. It is composed of a rotating magnetic field generating coil 2.2' for driving the bubble, a bias magnetic field generating magnet 3.3' for stably holding the bubble, and the like.

The memory element 1 is made of, for example, gadolinium, gallium, etc.
A bubble crystal film of magnetic garnet or the like is formed on a garnet single crystal substrate by a liquid phase epitaxial growth method, and a V-shaped film of permalloy or the like is formed thereon. The configuration of this transfer path can be roughly divided into a serial loop type and a major/minor type. Figure 3 shows an example of this major-minor one-sided system, with a bubble domain generator 5, a detector 6
, an eraser 7, etc., and a large number of minor loops 10-□ to 10n connected to this through transfer gates 9.

Such S-air bubble memory devices are also required to have improved storage density due to the recent increase in the amount of information and demands for miniaturization of fc+f't.

(3) Prior art and problems It is said that the transfer path using the half-disk pattern described in @ is capable of transferring bubbles even if the gap is relatively wide. In the case of , the gap is 1.0 μm and the pattern width is 7 to 8
It is μm. However, when attempting to accommodate 4M bits in a device with the same area as above in order to improve storage density, the transfer path gap is 0.5 μm and the pattern period tf4.
It is necessary to reduce the size to about μm. This gap is 0.5μ
m exceeds the resolution limit of optical lithography during pattern creation, making device creation difficult.

For this reason, recently, C1ub with a shape as shown in Fig. 4 a-e has been developed.
A pattern called foot has been developed.

Although this pattern has the advantage of allowing a larger gap than the half-disk pattern, it has the disadvantage that bubble transfer characteristics vary depending on the direction in which it is formed on the substrate.

(4) Purpose of the Invention In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide a magnetic bubble memory element that uses a pattern with a sufficient margin in the pattern gap and has no difference in bubble transfer characteristics depending on the bubble transfer direction. It is something to do.

(5) Structure and object of the invention According to the present invention, in a magnetic bubble memory element having a bubble magnetic domain transfer path in which soft magnetic patterns are periodically arranged on a bubble magnetic domain crystal, The bubble magnetic domain transfer path is arranged on the bubble magnetic domain crystal so that the axis of easy magnetization is parallel or antiparallel to the bubble magnetic domain transfer direction, and further, in the magnetic bubble memory element, the bubble magnetic domain transfer path is arranged in the bubble magnetic domain crystal plane. This is achieved by providing a magnetic bubble memory device characterized in that one feature is the application of a silent magnetic field in a direction perpendicular to the bubble domain transfer direction.

(6) Examples of the invention Embodiments of the invention will now be described in detail with reference to the drawings.

FIG. 5 is a diagram showing the transfer margin when the transfer path using the club foot pattern shown in FIG. 4 is loaded with the bubble magnetic domain crystal plane as shown in FIG.

Figure 5 shows the bias magnetic field on the vertical axis and the drive magnetic field on the horizontal axis9.
song#! I to ■ indicate the transfer margins of the transfer path of the pattern arrangement of 1 to ■ in FIG. 6, respectively.

In FIG. 6, arrows (112) and (211).

(121) respectively indicate the crystal axes of bubble domain crystals, and each is also an in-plane magnetization crystal axis, and each 12
00 intervals. Transfer paths ■ and ■ are easy magnetization axes (11
2), and the transfer paths (1) and (2) are not parallel or antiparallel to any axis of easy magnetization.

From the $5 diagram, it can be seen that the transfer path (■) has the best transfer margin compared to the others.

FIG. 7 is a diagram showing the margin when a static magnetic field is applied in a perpendicular direction to the transfer path (2) in FIG. 6 as indicated by the white arrow. In the figure, the vertical axis represents the bias magnetic field, the horizontal axis represents the drive magnetic field, and the margins when a static magnetic field (hold magnetic field) of 0 to 100 e is applied are shown by curves $a to f. The applied quiet magnetic field is as follows: curve a is 00e, b is 20e, e is 40@, d
is 60s, s is 80e, and f is 100.-.

Although the transfer path (2) has a poor margin as shown in FIG. 6, it can be seen that the margin can be improved by applying a hold magnetic field in the right angle direction as shown in FIG. In this way, the transfer paths in each direction each have hold magnetic field dependence. The present invention takes advantage of this property.

FIG. 8 shows one embodiment of the present invention, and shows 600 mm in the direction of the white arrow.
FIG. 6 is a diagram showing a case where a hold magnetic field of e is applied.

For the song +1'1ill in the figure, the minimum driving magnetic field when the hold magnetic field is 0 is 300e (see Figure 5), which is 1.
It has dropped to 500. On the other hand, in the case of the track 111V, the minimum driving magnetic field when the hold magnetic field is O was about 100°, but it is slightly degraded to 150e, but shows almost the same margin as the former.

In the magnetic bubble memory device of the present invention, the transfer path is arranged parallel or antiparallel to the crystal axis of the bubble domain crystal in this way, and a large hold magnetic field is applied to the transfer path by +1! This is a book in which the magnetic field is applied in an angular direction, which makes it possible to reduce the driving magnetic field and to match the margins of minor looseness.

(7) Effects of the Invention 1 Trial As explained in detail in the trial, the magnetic bubble memory filtration device of the present invention, in a transfer path using a pattern with a gap margin, uses a hold magnetic field to suppress the transfer path in a direction with a poor margin. By reinforcing the margin, it is possible to obtain transfer characteristics that are independent of the bubble transfer direction (pull transfer), which is a great book.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining a conventional magnetic bubble memory device, Fig. 2 is a diagram showing a pull memory element with a major minor configuration, Fig. The figure shows a pattern with a margin in the gap, Figure 5 shows the transfer direction dependence of transfer characteristics in a transfer path on a pull domain crystal, and Figure 6 shows the relationship between the crystal axis direction and the transfer path. FIG. 7 is a diagram showing the characteristics when a hold magnetic field is applied in a direction perpendicular to the transfer path, and FIG. 8 is a diagram showing the characteristics of one embodiment of the magnetic bubble memory element of the present invention. Yes. Figure 2 M Figure 3 弗 4 Figure 5 Drive magnetic field HD (○e) Figure 6 ■

Claims (1)

[Claims] 1. In a magnetic bubble memory element having an 8-bubble transfer path in which a soft magnetic pattern is periodically arranged on the 8-bubble-domain crystal, the axis of easy magnetization in the plane of the bubble magnetic domain crystal is aligned with the bubble. A magnetic bubble memory element characterized in that the bubble domain transfer path is arranged on a cough bubble magnetic domain crystal so as to be parallel or antiparallel to the magnetic domain transfer direction. 2. The magnetic bubble memory device according to claim 1, wherein a magnetic bubble is characterized in that a quiet magnetic field is applied in a direction perpendicular to the bubble magnetic domain transfer direction that is within the crystal plane of the bubble magnetic domain. memory element.