JPS627638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble device, and particularly to a magnetic bubble device that starts and stops magnetic bubbles as appropriate.

A common method for driving a magnetic bubble is to use a rotating magnetic field and a pattern of soft magnetic material such as permalloy formed on the surface of a magnetic bubble chip. This is a method in which, for example, a T-bar permalloy pattern is formed on the surface of a crystal in which magnetic bubbles can exist by a method such as vapor deposition or sputtering, 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 currents, triangular wave currents, trapezoidal wave currents, etc. having a phase difference of 90° through the X coil and Y coil arranged orthogonally to each other. As the rotating magnetic field rotates, the magnetic bubble propagates along the permalloy pattern, and when the rotating magnetic field stops, the magnetic bubble also comes to rest at the corresponding location. Especially recently, writing information,
Starting and stopping of the rotating magnetic field is frequently repeated in response to read and shift operations.

Generally, various functional units such as a magnetic bubble generator, propagation path, divider, stretcher, magnetic bubble detector, and eraser are arranged on a magnetic bubble chip, and as described above, information writing, reading, and shifting operations are performed. If the rotating magnetic field is started and stopped appropriately according to the rotational magnetic field, the elongated magnetic bubbles, especially those located under the divider, stretcher, and magnetic bubble detector pattern, will shrink as the rotating magnetic field stops.
Even if the rotating magnetic field is started again later, this reduced magnetic bubble will not reach the detector pattern without being extended to the initially set sufficient length, so the detection output will not be the same as during continuous operation. can't get it.

In particular, magnetic bubble devices operate under a high bias magnetic field in order to improve storage density, so a divider pattern, a detector pattern, and a few bits of stress just before the detector pattern are used to fully stretch the magnetic bubble and then cut it. The magnetic bubbles that have started to activate under the tsutiya pattern cannot be fully extended.

Therefore, in this type of magnetic bubble device, the drive is controlled so that the rotating magnetic field does not stop while the stretched magnetic bubble is present in the stretching section where the magnetic bubble is stretched as described above. However, the magnetic bubble device that performs such drive control has a complicated control system and new problems such as the inability to use the memory loop effectively.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a magnetic bubble device that ensures efficient use of storage loops.

Another object of the present invention is to provide a sufficiently wide operating margin;
Therefore, it is an object of the present invention to provide a magnetic bubble device with stable operation.

An object of the present invention is to provide means for applying a bias magnetic field, means for applying a rotating magnetic field, and means for applying a holding magnetic field in an in-plane direction to a bubble element having an extension part that stretches a magnetic bubble; A magnetic bubble device configured to start and stop a magnetic bubble by controlling a magnetic field, wherein the starting and stopping directions of the rotating magnetic field in the extension part and the application direction of a holding magnetic field applied in an in-plane direction, This can be achieved by arranging the extension section in a direction substantially perpendicular to the direction in which the magnetic bubbles extend.

Hereinafter, the present invention will be explained in detail with reference to the drawings. FIG. 1 shows a rotating magnetic field trajectory and a drive current waveform applied to a magnetic bubble device that is controlled to start and stop. Figure a shows the sinusoidal currents with their phases shifted by 90 degrees, which are supplied to both the X and Y drive coils, and the locus of the circular rotating magnetic field obtained by these sinusoidal currents. Further, FIG. 1B shows triangular wave currents whose phases are shifted by 90 degrees, which are supplied to both the X and Y drive coils, and the locus of a square rotating magnetic field obtained by these triangular wave currents.

In a magnetic bubble device that is controlled to start and stop, the current of the drive coil is cut off and on as needed, as shown in Figures a and b.

Therefore, if the rotating magnetic field is removed midway through a magnetic bubble that is being extended and propagating in the extension section, the magnetic bubble will shrink. Afterwards, even if a rotating magnetic field is applied to the reduced magnetic bubble, it will not be able to instantly expand to its original length, and even if it is stretched somewhat from the stopping point, it will still be insufficiently long and will not be able to be split or copied. Therefore, the desired function cannot be achieved in the extension section.

However, after the rotating magnetic field stops, if a holding magnetic field of an appropriate magnitude is applied in the same direction as the direction in which the rotating magnetic field stopped, the magnetic bubbles stretched in the extension part will not shrink and will remain stable under the divider pattern or stretcher pattern. exist.

The present invention utilizes this fact to control the driving magnetic field to realize a magnetic bubble device with stable operation. Figure 2 shows some examples of rotation trajectories when a holding magnetic field is applied. show.

Figures a to d represent a holding magnetic field obtained by arranging magnetic bubble chips at an angle with respect to the direction of a bias magnetic field, or by applying a DC magnetic field in a specific in-plane direction, which will be described later, and are explained in Figure 1. It shows the locus of the magnetic field that is synergized by the rotating magnetic field. Figures a and b show a system in which the holding magnetic field is not canceled by a rotating magnetic field, and the current waveforms supplied to both the X and Y drive coils are the sine wave current and triangular wave current shown in Figure 1. Figures c and d show a method in which the holding magnetic field is canceled by a rotating magnetic field, and the current waveforms supplied to both the X and Y drive coils are not only shifted in phase, but also adjusted to an appropriate value. Set. In the magnetic bubble device to which the rotating magnetic field locus illustrated in the figure is applied, a direct current holding magnetic field can be applied in a specific direction even after the drive current is reduced.

FIG. 3 shows an example of a method for applying a DC holding magnetic field, in which a magnetic bubble chip is arranged at an angle with respect to the direction in which a bias magnetic field is applied. In the figure, 1 is a magnetic bubble chip, H _B is a bias magnetic field, H _B
1 is a bias magnetic field perpendicular to the chip 1 which is effectively acted on by the bias magnetic field H _B , and Hh is a holding magnetic field horizontal to the chip 1 which is effectively acted on by the bias magnetic field H _B . By arranging the magnetic bubble chip at an angle with respect to the bias magnetic field in this manner, a holding magnetic field according to the present invention can be easily obtained.
Incidentally, the present inventors have confirmed that the magnitude of the holding magnetic field of about 5 [Oe] is sufficient.

FIG. 4 is a diagram for explaining in more detail the rotating magnetic field trajectories shown in FIGS. 2c and d, and shows the case where a triangular wave current is used. Figure a shows the locus of the rotating magnetic field obtained by supplying the triangular wave current shown in Figure b to both the X and Y drive coils, and Figure c shows the magnitude and direction of the DC holding magnetic field. This is the holding magnetic field Hh obtained by the tilted arrangement of the chips.

Figure d shows a magnetic field locus when the rotating magnetic field shown in figure a and the holding magnetic field shown in figure c are synergized.
In this case, during normal operation, the holding magnetic field Hh is canceled by the rotating magnetic field, so it does not have any effect on the magnetic bubbles moving within the chip. However, when stopped, that is, when the rotating magnetic field is removed, the holding magnetic field Hh acts effectively. FIGS. 5a and 5b are diagrams for explaining the present invention in more detail, and show the relationship between the magnetic bubble splitter and the rotating magnetic field locus.

In both figures, 2 is a permalloy pattern formed on a magnetic bubble chip by vapor deposition or the like, 3 is a conductor pattern made of a conductor such as gold by vapor deposition, etc.
Both figures constitute a divider.

FIG. 3A shows the configuration pattern of the divider when a chevron permalloy pattern is adopted as the transfer pattern, and FIG. 1B shows the configuration pattern of the divider when a half disk pattern is adopted. In both figures, B
is a magnetic bubble (also called a stripe magnetic domain) extended by the permalloy pattern 2.

Figure a shows that the rotating magnetic field H _R is started at a position of 180 degrees.
The case of stopping is shown, and the locus of the rotating magnetic field is shown on the right side of the figure. Also, the holding magnetic field applied at this time
The direction of Hh is applied in the same direction as the starting and stopping direction of the rotating magnetic field H _R , and this situation is also shown in the lower right of the figure.

The dividing operation is performed as follows.

The magnetic bubbles input from the direction of the arrow in the figure are gradually extended along the propagation direction by the chevron-shaped permalloy patterns 2 stacked in multiple stages perpendicular to the propagation direction, and the elongated magnetic bubbles B are as shown in the figure. When reaching the position, a current is supplied to the conductor pattern 3 in a predetermined direction to generate a magnetic field in the central loop formed by the conductor pattern 3, thereby dividing the elongated magnetic bubble B from its center into two parts. Send out the magnetic bubble after being divided into output propagation paths.

Further, Fig. b shows a case where the rotating magnetic field H _R is started and stopped at a position of 90 degrees, and the locus of the rotating magnetic field is shown on the right side of the figure. Further, the direction of the holding magnetic field Hh applied at this time is the same direction as the starting and stopping direction of the rotating magnetic field H _R , which is also shown in the lower right of the figure.

The dividing operation is performed as follows.

A magnetic bubble input in the direction of the arrow in the figure is propagated on the permalloy pattern 2 called a half-disk pattern, and is elongated at the top of the permalloy pattern 2' called a pictex pattern. At this time, a current is supplied in a predetermined direction to the conductor pattern 3 to generate a magnetic field in the central loop formed by the conductor pattern 3, thereby dividing the elongated magnetic bubble B from its center and producing two orthogonal outputs. The magnetic bubbles are sent out after being divided into propagation paths.

In this way, each division function shown in the diagram is performed.
Unless special control is carried out, it is quite possible for the rotating magnetic field to stop during the dividing operation, that is, when the magnetic bubble is fully extended. In this case, the expanding magnetic bubble shrinks at the same time as the rotating magnetic field becomes zero. However, as described above, the magnetic bubble expanded by applying the holding magnetic field can be held in that state.

At this time, the magnetic bubble extends in the starting and stopping directions of the rotating magnetic field H _R and in the application direction of the holding magnetic field applied in the in-plane direction (180 degree direction in figure a, 90 degree direction in figure b). The drive is controlled so that it is approximately perpendicular to the direction of movement. By performing drive control in this way, for example,
The elongated magnetic bubbles present in the stretcher pattern section in the front stage of the divider and in the divider pattern sections a and b in the same figure can be maintained in the same state even after the rotating magnetic field is stopped, and therefore the rotating magnetic field can be started again. Normal operation can be performed immediately after this.

As explained above, according to the present invention, there is no need to consider special conditions such as controlling the drive so that the rotating magnetic field does not stop while the magnetic bubble exists in the extension part, and therefore the memory The loop can be used effectively, and since no special device is required for drive control, the control is easy, and the peripheral circuit for driving the magnetic bubble can be simplified.

[Brief explanation of the drawing]

FIG. 1 shows a rotating magnetic field trajectory and a drive current waveform applied to a magnetic bubble device that is controlled to start and stop. FIG. 2 shows some examples of rotating magnetic field trajectories with the addition of a holding magnetic field. FIG. 3 is a diagram illustrating one means for obtaining a holding magnetic field. Figure 4 shows c and d.
FIG. 3 is a diagram for further explaining the rotating magnetic field locus shown in FIG. FIG. 5 is a diagram for explaining the relationship between the elongated magnetic bubble and the rotating magnetic field locus in the magnetic bubble device drive control system according to the present invention. In the figure, 1 is a magnetic bubble chip, 2 is a permalloy pattern, 3 is a conductor pattern, H _B is a bias magnetic field, Hh is a holding magnetic field, H _R is a rotating magnetic field, and B is a magnetic bubble.

Claims (1)

[Claims] 1 comprising means for applying a bias magnetic field, means for applying a rotating magnetic field, and means for applying a holding magnetic field in an in-plane direction to a bubble element having an extension part that stretches a magnetic bubble, and controlling the rotating magnetic field. A magnetic bubble device configured to start and stop a magnetic bubble, wherein the starting and stopping directions of the rotating magnetic field in the extension part and the application direction of a holding magnetic field applied in an in-plane direction are controlled by the magnetic bubble in the extension part. A magnetic bubble device drive control method characterized in that the direction is substantially perpendicular to the direction in which the bubble expands.