JPS58111179A - Magnetic bubble memory device - Google Patents

Abstract

PURPOSE:To hold a bubble at a prescribed stop position even when an electric power supply is disconnected by forming a nonmagnetic intermediate film and the 2nd magnetic film between the 1st magnetic film and an insulating film and drilling a hole on the 2nd magnetic film at the same position as the bubble stop position. CONSTITUTION:A hard bubble film 2 is formed between a base plate 1 and the 1st magnetic film 3. A magnetic material used for the 2nd magnetic film 5 has a vertical magnetizable axis. An intermediate film 4 between the 1st magnetic film 3 and the 2nd magnetic film 5 is made of a nonmagnetic material. A hole C is drilled on the 2nd magnetic film 5. When there is no external rotating magnetic field, a bubble B is held at a position S, a permalloy pattern P is slightly magnetized by the hole C and also a local magnetic field generated due to said magnetization applies force in the direction to pull the bubble B to the position S. The position of the hole C is fixed on a position where the bubble is stopped at the time of no rotating magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory device, and particularly to a start,
O1! to hold the magnetic bubble (hereinafter referred to as bubble) in a predetermined position during stop operation or power outage! 4 concerning bubble memory chips with elements.

In the puzzle memory device, as a means of transferring bubbles as information carriers, a rotating magnetic field parallel to the 10 sides of the bubble memory chip is applied to transfer the bubbles formed on the magnetic film of the puzzle memory chip. The Roy transfer pattern is magnetized to generate a local magnetic field, and the local magnetic field produces a predetermined par! The method of transferring bubbles on the transfer path is well known, and all paplume cage devices that have been put to practical use use this method. The start-stop action of starting, stopping, and turning is an important function of bubble memory.
It is important to hold the four bubbles in a predetermined position in the absence of a rotating magnetic field by cutting off the power source, etc., so as not to destroy the information in the bubble memory. - As a method to achieve the above function, there is a conventional method of applying a DC magnetic field parallel to the surface of the bubble memory chip.
In the actual bubble memory device 1, two types of systems are put into practical use: main and 1. Both of these 211-type systems utilize a magnetic field generated by a permanent magnet for generating a bias magnetic field. One is to tilt the bubble memory chip mounting board by the required angle with respect to the bias magnetic field generating magnet, and the other is to attach it to the bias magnetic field generating magnet and taper the nine magnetic plate. This method applies a tilted DC bias magnetic field equal to the angle of the taper to the surface of the bubble memory chip.

By the above method, it is possible to keep the permalloy transfer pattern magnetized even in the absence of a rigid plate magnetic field, thereby making it possible to maintain the bubble for a predetermined amount tK.

However, in the above method, when assembling the bubble memory device,
It is necessary to maintain a certain angle between the board on which the bubble memory chip is mounted and the bias magnet or tapered magnetism plate, but when installing bubble memory devices, the angle must be exactly the same for all bubble memory devices. It is difficult to set this, and inevitably there are variations in characteristics between each bubble memory device.

The present invention creates an element in a bubble memory chip that has a function similar to the above-mentioned function of applying an in-plane magnetic field to a bubble memory chip to hold the bubble in a predetermined position, thereby maintaining the same information retention ability at all times. The present invention provides a bubble memory device having the following features.

The bubble memory device of the present invention can be used as a bubble memory device as a bubble memory device.
Between the magnetic film and the insulating film, a non-magnetic intermediate film and a second magnetic film having an easy-to-Kil axis in the direction perpendicular to the film surface Kfi, like the first magnetic film, are provided. In the magnetic gland, the bubble is held at a predetermined stopping position by drilling a hole of an arbitrary shape using ion milling force at the same position where the bubble stops when there is no large rotating magnetic field for bubble transfer. That is.

FIG. 1 is a sectional view of a paplume kogori chip according to the present invention. In order to suppress hard bubbles in bubble memory chips currently in practical use, an ion implantation layer is formed on the first magnetic layer 113 of the bubble medium or a hard bubble suppression film is formed. Regarding the present invention, in consideration of the design and characteristic advantages of the bubble memory chip, the hard bubble suppression film 2 may be created between the GGG (cadrinium W lium garnet) substrate l and the first magnetic layer 1li13. is desirable. The magnetic material used for the second magnetic IK5 may be any material as long as it has an easy axis of magnetization that is perpendicular to the group 1tlKI1. Further, the intermediate 1114 between the first magnetic film 3 and the second magnetic aSS may be made of any material as long as it is non-magnetic, but even a magnetic film can be used as the intermediate film as long as bubbles can stably exist. For example, it is also possible to use the hard bubble suppression film as an intermediate film. Second magnetic film 6
The zero hole C may have any shape, but a cylindrical shape is easier to design and calculate. The cylindrical hole C and the bubble B interact and attract each other. Here, if the magnetization of the first magnetic film 3 is Ml and the magnetization of the second magnetic film 5 is M, then bubble B and hole C can be thought of as cylindrical magnets as shown in Figure 2. , the interaction force can be calculated by assuming that the magnetization of bubble BK is 2M, and the magnetization of hole CK is M.If we take the coordinate system as shown in Figure 2, we can calculate the interaction force of the bubble. Since movement in the y direction is impossible, only the 11x component of the force acting on the bubble BK is required.If this is Fx, the distance obtained by Fxd theoretical calculation can be obtained.The center of the bubble B and the hole If we represent the qualitative relationship between Fx and X on a graph, where X is the distance from the center of C, it will be as shown in Figure 3.If Fx is positive in the direction of attraction, then X■0 and Fx■0. Fx at 0
>O, and reaches the maximum value Fmax at a certain value Xp.

Next, the interaction of the bubble B with the hole C and the permalloy pattern P will be explained. For simplicity, it is assumed that the permalloy pattern Pd is rod-shaped, and the hole C is located below one end of the permalloy pattern P as shown in FIG. When there is no external rotating magnetic field, the bubble B is held at position 8, and the permalloy pattern P is slightly oxidized due to the large OK, and the resulting local magnetic field also provides a force in the direction of attracting the bubble B to position 8. When the magnetic field Ha is applied once, the bubble B is moved by the local magnetic field created by the permalloy pattern P. At the time of Jin, the X component of the force acting on bubble B due to PK is the X component FXIP of the force acting on bubble BK due to 60 FXl
Bubble memory chips must be designed so that they are always larger than C. Also FXIC and FzlC
The value of the distance XP between the bubble B and the hole C when becomes maximum also needs to be optimally designed for various shapes of permalloy transfer patterns.

Examples of the present invention will be described.

The storage area of the bubble memory chip was configured as shown in FIG. Regarding the material and characteristics of the film, the hard bubble suppressing film 2 is YIG (III thickness 300), and the third magnetic film 3 is (YLu8mCu) @ (FeGe) 60
11 (film thickness 1.65 fim * 4 gMm -46
0CG) ), the intermediate film 4 is 810. Expansion (film thickness 2000A
), the second magnetic aS has Tb-re expansion (a thickness 3000A,
The coercive force is 650j be ). The permalloy transfer pattern is asymmetric spron-shaped, and the bubble diameter is 1.7 [μ
m], the diameter of the hole in the second magnetic film is 2 [μm], and its position is as shown in FIG.

In the design for carrying out the present invention, the most important point is the position of the hole C formed in the second magnetic film. Generally, the storage area of the bubble memory chip is in a loop shape, so the bubble stopping position differs depending on the bubble transfer direction and the direction of the in-plane magnetic field. That is, cases such as those shown in FIGS. 6 and 7 can be considered. Figure 6,
In FIG. 7, the broken line circle C represents the hole of the second magnetic II5. The size of the hole is determined by the bubble diameter, the magnetization and concentration of the first magnetic film, the thickness of the intermediate film O, the magnetization and film thickness of the second magnetic film, the shape of the permanent P pattern, etc. Since it is desirable that the distance between the permanent p-pattern and the bubble be as short as possible, the thickness of the intermediate film and the second magnetic layer should be the same as the first magnetic layer.
It is necessary to make it as thin as possible compared to K. Therefore, in order to increase the interaction force between the bubble and the hole as much as necessary, the magnetization of the second magnetic film may be increased or the size of the hole may be designed to be larger than the bubble diameter.

In general, if the second magnetic film is thin, the magnetization of the second magnetic layer may be reversed by the local magnetic field caused by bubbles. It needs to be a large magnetic material.

The method for constructing the gland is D), a method using all garnet-based materials, using KYIG (yttrium iron garnet) for hard bubble suppression, magnetic garnet for the first magnetic film and second magnetic film, and GGG for the intermediate layer. .

(2) A method in which the second magnetic film is an amorphous magnetic film in (t).

(3)% A method of forming an amorphous magnetic film as the second magnetic film using an insulating layer such as an intermediate jllK8101 film or an aAjsOs film in (1).

(4) In the range 1i in which bubbles are present in the -ia film in %(1) and (2), a method in which a magnetic garnet designed to prevent bubbles from forming is used as the intermediate film.

etc. are opened.

The operating margin characteristics of the nine practical examples described above were similar to those of the conventional Papulume sled device having an in-plane magnetic field. In the first wJ, the hard bubble suppression film 2 is attached to the GGG substrate l.
A method of suppressing bird bubbles by creating a hard bubble suppressing film between the first magnetic layer 3 and the intermediate layer 114 and implanting ions into the nine-puplume sled chip and the first magnetic layer 11. A similar effect can be obtained with paplume chewing chips using .

The present invention relates to a large magnetic field driven bubble memory device using an existing Permalloy transfer pattern.
9 cities, Bell System Technical Journal (Be
1l 5yst@m technlcalJourna
l) It is extremely effective for the two-layer conductor current-driven bubble memory device that was first announced in Vol. 58, p. 1453 onwards. If it is cold, it is pointless to apply an in-plane magnetic field because it does not use a magnetic material transfer pattern like the two-layer conductor current-driven bubble memory device company Permaui, and it is useless to apply an in-plane magnetic field, and the bubble will be removed when the power is turned off. This is because it is difficult to keep it in place.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a bubble memory chip according to the present invention;
2nd a! ! 1, FIGS. 3, 4 and 5 illustrate the principles of the present invention, and FIGS. 6 and 7 illustrate embodiments of the present invention. In the figure, l...GGG board, 2...
・Hard bubble suppression exhibition, i... Third magnetic layer as bubble medium, 4... Intermediate layer, 5...
・Second magnetic field with bubble retention element, 6...
It is an insulating layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] Between the first magnetic layer as a magnetic bubble medium and the insulating film,
In addition to providing an intermediate film and a second magnetic film, the second magnetic film J
In II, a magnetic bubble meshing device uses a 1# mold to make a hole of an arbitrary shape at the stop position of a magnetic bubble when there is no rotating magnetic field for magnetic bubble transfer.