JPS595984B2 - magnetic bubble device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble device using a half-disk pattern in a magnetic bubble propagation path, and particularly to a magnetic bubble device in which magnetic bubbles are started and stopped as appropriate in the propagation path.

As a method for driving a magnetic bubble, there is a method that utilizes a rotating magnetic field and a pattern of soft magnetic material such as permalloy formed on the surface of a magnetic bubble chip (magnetic bubble element).

This is a method in which a predetermined permalloy pattern is formed by a method such as vapor deposition or sputtering on a crystal plane where magnetic bubbles can exist, and a rotating magnetic field is applied from the outside in the direction within the crystal plane. The rotating magnetic field is obtained by passing sine wave current, triangular wave current, or trapezoidal wave current having a phase difference of 900 degrees through the husband and wife of the X coil and Y coil arranged perpendicularly to each other around the magnetic bubble chip. The action of this rotating magnetic field causes the magnetic bubble to be transferred along a soft magnetic material pattern or propagation path. When the rotating magnetic field comes to rest, the magnetic bubbles come to rest at pattern positions corresponding to the direction of rest of the rotating magnetic field. In a magnetic bubble device, starting and stopping of the rotating magnetic field is frequently repeated in response to information writing, reading, shifting operations, etc. When the rotating magnetic field is started or stopped in this way to drive or stop the magnetic bubbles, the magnetic bubble information under the pattern may be disturbed by the disturbing magnetic field applied to the magnetic bubble chip.

This disturbing magnetic field is generated by (1) an oscillating magnetic field based on the electrical oscillations that occur in the rotating magnetic field generator when the rotating magnetic field is started or stopped, and (2) when the magnetic bubble chip is placed at an angle to the bias magnetic field. The magnetic field generated in (3j) is based on the disturbance magnetic field applied from the outside of the magnetic bubble device, etc. Among these disturbance magnetic fields, the oscillating magnetic field due to the electrical and vibration of the rotating magnetic field generator is Although it can be suppressed to some extent by changing the configuration, it cannot be completely suppressed, and in this case, there is a problem that the circuit configuration of the rotating magnetic field generator becomes complicated. A magnetic bubble device that has high stability of magnetic bubble information against a disturbing magnetic field when a rotating magnetic field is started or stopped,
Therefore, it is an object of the present invention to provide a magnetic bubble device in which the nonvolatility of magnetic bubble memory is highly reliable.

The features of the present invention that achieve the above object include a magnetic bubble element (magnetic bubble chip) having a magnetic bubble propagation path with a half-disk pattern, a means for applying a bias magnetic field to the magnetic bubble element, and a means for applying a bias magnetic field to the magnetic bubble element. A magnetic bubble device comprising: means for applying a rotating magnetic field, and controlling the rotating magnetic field to start and stop a magnetic bubble, wherein the direction of the rotating magnetic field when starting and stopping the magnetic bubble is as described above. The reason is that it is configured to be perpendicular to the magnetic bubble propagation direction of the half disk pattern propagation path.

The half-disk pattern in this specification is a semi-circular,
A U-shaped or U-shaped pattern or a development of these patterns, in which at least a portion of the two arms that sandwich the opening are arranged parallel to each other. .

The present invention will be explained in detail below using the drawings.

FIGS. 1a and 1b show an example of a pattern arrangement of a half-disc pattern used in the magnetic bubble device of the present invention, and each shows an asymmetric half-disk pattern. When a soft magnetic material having these half-disc patterns is formed on the surface of a magnetic bubble chip and an in-plane magnetic field rotating counterclockwise with respect to the drawing is applied, the magnetic bubbles existing on the pattern propagate in the direction of the arrow. do. Figures 2a and 2b represent the trajectory of the in-plane rotating magnetic field applied to the magnetic bubble device when controlling the start and stop of the magnetic bubble, and the current waveforms flowing in both the Z and Y drive coils in that case. There is.

Regarding these figures, Figure 2a shows the case where sinusoidal currents with a phase shift of 90X are used as the drive currents for the X and Y coils, and Figure 2b shows the case where triangular wave currents with a positive phase shift of 90X are used. are shown respectively. A rotating magnetic field as shown in FIG. 2a or 2b is applied within the plane of a magnetic bubble chip having a half-disk pattern as shown in FIG. 1a or 1b and having predetermined magnetic bubbles in the pattern portion. When this happens, the magnetic bubble is activated, moves by a unit pattern, ie, one bit, and then stops.
As mentioned above, magnetic bubbles are susceptible to interference magnetic fields when starting and stopping.

However, the present inventors have discovered that by defining the start and stop directions of the in-plane rotating magnetic field of the chip for this type of half-disk pattern arrangement, the stability of the magnetic bubble against the interfering magnetic field can be dramatically improved. FIG. 3a shows an example of measurement of the anti-interference magnetic field characteristics when starting and stopping a half-disk pattern when the starting and stopping directions of the rotating magnetic field within the chip plane are taken as parameters. Further, FIG. 3b shows the relationship between the arrangement of the half-disk patterns in FIG. 3a and the direction of the driving magnetic field. In Figure 3a, the horizontal axis represents the disturbance magnetic field in the plane of the chip applied to the magnetic bubble chip, the vertical axis represents the bias magnetic field applied perpendicularly to the magnetic bubble chip, and M is the bias magnetic field during continuous operation. It represents the margin width. Also, A, B
, C, and D respectively represent the anti-jamming magnetic field characteristics when a predetermined value of the chip in-plane driving magnetic field is applied in the direction shown in FIG. 3b. As is clear from Figures 3a and 3b, the half-disk pattern has good anti-jamming magnetic field characteristics when the driving magnetic field is applied in the 0 and 1800 directions, that is, in the direction perpendicular to the magnetic bubble propagation direction. Become.
Therefore, if the starting and stopping directions of the rotating magnetic field applied to the half-disk pattern are perpendicular to the magnetic bubble propagation direction, the stability of the magnetic bubble against the interfering magnetic field will be increased. Based on the above idea, the configuration of the device of the present invention will be explained below. FIG. 4 is a diagram showing the configuration of a driving magnetic field generating section in an embodiment of the magnetic bubble device of the present invention, and 1
is based on a soft magnetic material k... - Magnetic bubble chips with disk pattern propagation, memory paths, etc. formed on the surface, 2 and 3
4 is a drive current generation circuit for the X coil 2, and 5 is a drive current generation circuit for the Y coil 3. It is a circuit.

In this embodiment, the drive current generating circuits 4 and 5 generate a triangular wave current, but in the device of the present invention, a sine wave current or a trapezoidal wave current can also be applied to the drive current. Although not shown in FIG. 4, this magnetic bubble device uses a well-known bias magnetic field made of, for example, a permanent magnet, which applies a static magnetic field perpendicular to the chip in order to create a stable magnetic bubble within the chip 1. Equipped with a supply circuit. Drive current generating circuits 4 and 5 include switch elements S, , S2, S3, S4, and switch element S connected as shown in FIG.
5l, S'2, S(, S'4), and these switch elements are controlled by a well-known control circuit (not shown) as shown in FIGS. A rotating magnetic field with starting and stopping directions can be obtained.

5a to 5d are diagrams for explaining the operation of the drive magnetic field generator shown in FIG. 4, and FIG. 5a shows the X coil 2 and Y coil 2.
The driving current waveform supplied to the coil 3, FIG. 5b shows the locus of the in-plane rotating magnetic field formed in the chip 1 by this driving current waveform, and FIGS. 5c and 5d show the driving current generating circuits 4 and 5. It shows the relationship between each switch element control time chart and each drive current generated by the control.

Symbol E in Figures 5b, 5c, and 5d.
F, G, H, I, J, and K represent the temporal identity of each current waveform and rotating magnetic field locus. When switch elements S and S3 turn on at time EVC, current begins to flow through the path of switch element Sl, X coil 2, and switch element S2.

This current gradually increases according to a time constant determined by the inductance and internal resistance of the x coil, and when switch elements Sl, S2, S3, and S4 are all turned off at time F, it gradually decreases according to the above time constant. do. Similarly, from time G to time 1, a triangular wave current in the opposite direction is obtained by the operation of switch elements S2 and S4. switch element s'1,st
, s'3 and St. A similar operation is performed for the 5Y coil 3 to obtain a triangular wave current as shown in FIG. 5d. Therefore, the locus of the vector sum of these triangular wave currents and the magnetic fields excited by the X coil 2 and Y coil 3 is as shown in FIG. 5b. FIG. 6a shows an example of a pattern of a magnetic bubble propagation path made of a soft magnetic material formed on the surface of the chip 1 in the embodiment of FIG. This is the case where the propagation path 6 is formed.

The propagation path 6 consists of a straight portion 6a and a curved portion 6b, but since this type of propagation path is mostly formed from the straight portion 6a, magnetic bubbles are present in the curved portion 6b. It is rare that there are. Therefore, if a rotating magnetic field having a trajectory as shown in FIG. 6b or 6c is used as a magnetic bubble driving magnetic field, the starting and stopping directions of the driving magnetic field are perpendicular to the magnetic bubble propagation direction of the half-disk pattern, so that the disturbing magnetic field This will improve the stability of the magnetic bubble. Furthermore, it is more preferable to provide a well-known magnetic bubble detector in the curved portion 6b and to control the device so that it will not start or stop if a magnetic bubble is present in this portion. FIG. 7a shows another pattern example of the magnetic bubble propagation path of the chip 1, in which a major loop propagation path 7 and a minor loop propagation path 8 are formed by a half disk pattern.

In general, in this type of pattern configuration, there is often no need to store magnetic bubble information in the major loop propagation path 7, so the stability of magnetic bubbles should only be considered with respect to the minor loop propagation path 8. Good. Therefore, the sixth
For the same reason as in the example in Fig. 7a, if a rotating magnetic field having a locus as shown in Fig. 7b or 7c is used as a magnetic bubble driving magnetic field, the starting and stopping direction of the driving magnetic field will be in the linear portion 8a.
This is perpendicular to the magnetic bubble propagation direction of the half-disk pattern, which improves the stability of the magnetic bubble against the interfering magnetic field. Further, it is preferable to provide a well-known magnetic bubble detector in the curved portion 8b and control the above-mentioned starting and stopping when magnetic bubbles are present in this portion. As explained above, the magnetic bubble fold arrangement of the present invention starts and stops the rotating magnetic field in a direction perpendicular to the magnetic bubble propagation direction of the half-disk pattern, so the stability of magnetic bubble information against disturbing magnetic fields is high. Therefore, magnetic bubble memory has the advantage of high reliability in terms of non-volatility.

Furthermore, it has the advantage that the design margin of the driving magnetic field generating section, which required various measures to suppress the disturbing magnetic field, can be expanded and reliability can be improved. Further, as in the above-described embodiment, by using a triangular wave current for the drive current of the rotating magnetic field, the structure of the drive current generation circuit becomes simple, and the control of starting and stopping becomes very easy.

Furthermore, in the case of sine wave current drive, since resonance is used, it is difficult to suppress electrical oscillations when the current is interrupted, and the suppression circuit becomes complicated, but in the case of triangular wave current drive, this type of There is little vibration and it is very easy to suppress it.

[Brief explanation of the drawing]

Figures 1a and 1b are explanatory diagrams showing an example of a half disk pattern used in the device of the present invention, and Figure 2a
Figures 2b and 2b are explanatory diagrams showing examples of the rotating magnetic field locus and drive current waveform used in the device of the present invention, Figures 3a and 3b are diagrams of anti-jamming magnetic field characteristics of magnetic bubbles, and Figure 4 is a diagram of the magnetic bubble according to the present invention. 5a, 5b, 5c, and 5d are explanatory diagrams of the operation of FIG. 4, and FIG. 6a is a magnetic bubble propagation path of the device of the present invention. FIGS. 6b and 6c are explanatory diagrams of the rotating magnetic field locus of the propagation path, FIG. 7a is a diagram showing another pattern example of the magnetic bubble propagation path of the device of the present invention, and FIG. 7b and FIG. 7c is an explanatory diagram of the rotating magnetic field locus of the propagation path. 1...Magnetic bubble chip, 2,3...
Drive coil, 4, 5... Drive current generation circuit, 6
,7,8...Magnetic bubble propagation fan.

Claims (1)

[Claims] 1. A magnetic bubble element having at least a minor loop magnetic bubble propagation path consisting of a linear portion and a curved portion for storing magnetic bubble information, and applying a bias magnetic field to the magnetic bubble element. and means for applying a rotating magnetic field to the magnetic bubble element, and in the magnetic bubble device, the magnetic bubble propagation path is formed by arranging a plurality of half-disc patterns by controlling the rotating magnetic field. and a magnetism characterized in that the direction of the rotating magnetic field when starting and stopping the magnetic bubble is perpendicular to the magnetic bubble propagation direction of the linear portion of the magnetic bubble propagation path. bubble device. 2. The magnetic bubble device according to claim 1, wherein the rotating magnetic field applying means includes a triangular wave current generating circuit.