JPS6059666B2 - magnetic bubble expander - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble expander that serves to stretch magnetic bubbles into string-like elongated bubbles.

The signal output of a magnetic valve detector that converts the presence or absence of a magnetic bubble into an electrical signal increases in proportion to the length of the magnetic bubble. Therefore, a magnetic bubble expander is installed on the input side of the magnetic bubble detector, and a cylindrical It has been carried out to elongate the bubble into a string-like bubble that is 100 to several hundred times as long and detect it after seven seconds.

FIG. 1 is a diagram showing an example of a pattern of a conventional magnetic bubble expander. In the figure, 1000 is a magnetic bubble expander, 2
00 is a magnetic bubble detector. magnetic bubble expander 10
00 is constructed by arranging n rows 100 of chevron patterns 10 made of soft ferromagnetic thin films such as permalloy in the horizontal direction, and further arranging them in l stages in the vertical direction. usually,
n is about 100 to 4 degrees, and 1 is about 10 to 2 degrees Celsius. In the figure, HB is a bias magnetic field that is externally applied perpendicularly to the surface of the bubble medium in order to make the magnetic bubble exist stably, and in the case of the figure, it is applied from the back to the front of the page. Further, HR is a rotating magnetic field that is applied from the outside to transfer magnetic bubbles and is rotating counterclockwise within the plane of the bubble medium. This rotating magnetic field HR causes the magnetic valve B to move in the direction indicated by the arrow P in the magnetic bubble expander 1000.
Each time the rotating magnetic field HR rotates once, it moves up one stage.
When the magnetic bubble B is transferred upward through the magnetic bubble expander 1000, it is also stretched in the lateral direction indicated by Q in the figure, and expanded into a string-like bubble.

Since the speed at which the magnetic bubble B is stretched in the lateral direction Q is finite, the magnetic bubble B is
Each time the inside is transferred one step upward P, it is also slightly extended in the lateral direction Q, resulting in E, E in the figure. As exemplified,
It gets longer. When the magnetic bubble expander 1000 operates normally, the magnetic bubble B is stretched to the full lateral width of the expander 1000 (full stretch) before being transferred to the final stage 1 position of the magnetic bubble expander. It turns out.
In conventional magnetic bubble expanders, the bias magnetic field H
If B becomes larger, the rotating magnetic field HR becomes weaker, or the frequency of the rotating magnetic field HR becomes higher, the bubble extension will not be large enough, resulting in E″1 and E″2 in the figure.
There was a problem in that the stretching was limited to the extent shown in the example above, and it was not fully stretched.

In order to improve this situation, several improved versions of magnetic bubble expanders have been announced.

FIGS. 2A, 2B and 2C illustrate one row 100 in each of three examples of improved patterns of these conventional magnetic bubble expanders. The characteristics of these conventional improved magnetic bubble expanders are that, as the basic pattern constituting the rows 100 of the magnetic thin film pattern, an asymmetrical apron pattern is used instead of the symmetrical apron pattern 10 used in the example in FIG. The point lies in the use of patterns. It is well known that such an asymmetrical apron pattern has better properties for transferring magnetic bubbles than a symmetrical apron pattern, and these asymmetrical apron patterns with excellent transfer properties can be used as a basic pattern. By configuring the rows 100 of the magnetic bubble expanders 1000, the speed at which the magnetic bubbles B are stretched in the lateral direction Q is increased. The object of the present invention is to provide a region with a large bias magnetic field H8,
It is an object of the present invention to provide a magnetic bubble expander which can be fully stretched even in a region where the rotating magnetic field HR is small or a region where the frequency of the rotating magnetic field HR is high and has further improved characteristics.

As a result of a detailed study by the present inventor of the operation of the conventional magnetic bubble expander shown in FIGS. 1 and 2 to laterally extend magnetic bubbles, the following findings were found.

FIG. 3 shows the magnetic bubble B in the magnetic bubble expander 1000.
This is a diagram partially showing the transfer process of , and the reference numerals in the diagram are the same as in FIG.

Similarly, B(0) is B. when the rotating magnetic field HR is in the 0 direction. (90) and B(180) are the magnetic bubble positions when HR is in the 90 direction, respectively. In this way, the rotating magnetic field H
When R rotates half a turn from 0 to 1800, initially B
The magnetic bubble located at the (0) position will be transferred to the B (180) position. When the magnetic bubble B is transferred in the longitudinal direction P, it is simultaneously stretched in the transverse direction Q, but in this case it is not stretched transversely at a constant speed, but in relation to the phase of the rotating magnetic field HR. It was found that it was suddenly elongated only near that particular phase, and not at other phases. Now, the position and state of magnetic bubble B at phase XO of rotating magnetic field HR are expressed as B(x
) and hail. FIG. 4 shows the results of determining the phase at which the magnetic bubble B(x) is stretched in the lateral direction Q for a conventional magnetic bubble expander.
It extended only when it was within the phase range indicated by diagonal lines in the figure. In other words, for a conventional magnetic bubble expander,
``Out of the total phase range of 360 degrees, the range of phase X that is effective for stretching the magnetic bubble B(x) in the lateral direction Q is x=
There are only two very narrow ranges, one near 0 and one near the x=180 effect. B(0), B(18) in Figure 3
At position 0), the magnetic bubble is stretched in the lateral direction Q, but at other positions it is hardly stretched, and at position B(
90), it is not stretched at all. The basic idea of the present invention is to expand the phase range that is effectively used to stretch the magnetic bubble laterally within the total phase range of 360.

In contrast, the conventional improved magnetic bubble expander shown in FIG. 2 is an attempt to increase the speed of expansion in the lateral direction Q. Now, in a certain magnetic bubble expander, let the speed at which it stretches the magnetic bubble in the lateral direction Q be . Then, the amount ΔI by which the rotating magnetic field HR is stretched in the lateral direction during one rotation is expressed by the following equation. Here, T is the time for one rotation of the rotating magnetic field HR, that is, the time period of HR. Improving the full stretch characteristics is by increasing ΔI in equation (1), and the conventional improved magnetic bubble expander shown in Figure 2 attempts to increase VQ in equation (1). It is something.

FIG. 5a is a diagram showing a conventional basic pattern, a chevron pattern 10.

This pattern consists of two parts: the first elemental piece 1 at the front with respect to the transfer direction P of the magnetic bubble, and the second elemental piece 2 at the rear.
It is thought that they are joined at the points indicated by broken lines in the figure, and the first elemental piece 1 and the second elemental piece 2 are inclined in opposite directions with respect to the bubble transfer direction, and the widths of both pieces are equal. . FIG. 5b shows a so-called asymmetrical chevron pattern 1'', in which the width of the first element 1'' is wider than the width of the second element 2''. In this way, it is thought that magnetic bubbles can be easily transferred from one row 100 of a pattern to the next row 100, an improvement on the conventional magnetic bubble expander shown in FIGS. 2A, b, and c. It can be said that the shape pattern is designed to improve the speed Q based on this idea. In contrast, in the present invention, as described above, in order to expand the phase range Δθ used to extend the magnetic bubble in the horizontal direction, as shown in FIG.
We decided to improve the pattern shape so that it occurs not only near 80 but also near 45135.

Figure 7 A, bl Figure 8 A, b, Δθ is 45, 135
The shapes of improved basic patterns 11, 11'', 12, 12'' according to the present invention to be generated also in the vicinity of A are shown. In the pattern 11, the first elemental piece 1 has the same width as the second elemental piece 2, and has a protruding portion 1a extending from the joining point of the two, and in the pattern 1 ``the first elemental piece 1'' has the same width as the second elemental piece 2. A protruding portion 1″ that is wider than the two pieces 2″ and extends from the joint of the two pieces.
It has a. In the pattern 12, the second elemental piece 2 has the same width as the first elemental piece 1, and has a protruding portion 2a extending from the joining point of both, and the pattern 12'' has the same width as the first elemental piece 1.
'' is narrower than the first piece 1'' and has a protruding portion 2''a extending from the joint portion of the two pieces.The magnetic bubble expander of the present invention has basic patterns 10, 10'' as described above. ,1
1, 1", 12, 12" are used in combination, but as a result, the protruding part of the first element is connected to the second element of an adjacent (and sometimes even adjacent) pattern, or The protruding portion of the pattern is connected to the first element of an adjacent (sometimes even adjacent) pattern, resulting in a pattern in which the first element is connected to a plurality of second elements, and a pattern in which the second element is connected to a plurality of second elements. The pattern is formed by stacking rows of patterns in which patterns are combined with a plurality of first elemental pieces in multiple stages. Figure 9a is basic pattern 1
FIG. 9b shows a pattern in which basic patterns 10 and 11 are combined and a pattern in which basic patterns 10 and 12 are arranged alternately. Figure 10a shows the basic pattern 1",1
2" alternately, Figure 10b is basic pattern 1
It is a diagram showing a combination of 0'', 1'' and a combination of 1'', 125 arranged alternately. As a result of examining the operation of the magnetic bubble expander of the present invention using these patterns, it was found that the magnetic bubble As expected, it was found that the phase range was elongated within the shaded phase range in Fig. 6.
FIGS. 12A and 12B each show examples of further different patterns used in the present invention. As explained above, according to the present invention, it is possible to obtain a magnetic bubble expander with further improved characteristics that can be fully stretched in areas where the bias magnetic field is large, the rotating magnetic field is weak, and its frequency is high. .

``Brief Description of the Drawings Figure 1 is a diagram showing the pattern of a conventional magnetic bubble expander;
Figures 2A, b, and c are examples of conventional improved patterns of magnetic bubble expanders; Figures 3 and 4 are explanatory diagrams of the operation of conventional magnetic bubble expanders; Figures 5A and b are conventional basic patterns. The pattern diagram, Figure 6 is the operational characteristic diagram of the bubble expander of the present invention, and Figure 7 A, b.
, Figures 8A and b are basic pattern example diagrams according to the present invention, Figure 9
Figures A and b, Figures 10A and b, Figures 11A and bl, and Figures 12A and b are diagrams showing different patterns used in the embodiment of the present invention.

1,1″...first elemental piece, 1a,1″a...
...Protruding portion of the first elemental piece, 2,2''...Second elemental piece, 2
a, 2″a... second elemental piece protruding portion, 10, 1″, 1
1,11″,12,12″・・・Basic pattern, 10
0... Row of magnetic bubble expanders, 1000...
・Magnetic bubble expander.

Claims (1)

[Claims] 1. A soft ferromagnetic thin film is formed on the surface of the magnetic bubble medium using a basic pattern of a chevron pattern or an asymmetric chevron pattern, which is a combination of a first element and a second element tilted in opposite directions relative to the bubble transfer direction. In the formed magnetic bubble expander, the pattern is a mixture of a first elemental piece coupled to a plurality of second elemental pieces and a pattern in which a second elemental piece is coupled to a plurality of first elemental pieces. A magnetic bubble expander featuring: