JPS6037550B2 - magnetic bubble device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-layer conductor current-driven magnetic bubble device, and more particularly to a magnetic bubble detector.

FIG. 1a shows a plan view of a conventional two-layer conductor current-driven magnetic bubble device detector, and FIG. Shown below.

In FIGS. 1a and 1b, 1 is a magnetic thin film for magnetic bubbles such as garnet, 2 is a thin film magnetoresistive detection part, the material is a high magnetic permeability material such as permalloy, and 3 is a first conductor layer. , the material is AI-Cu, 4 is a second conductor layer, and an insulating layer 5 made of Si02 or the like is provided between each layer. 6 is the direction of the bias magnetic field applied from the paper surface toward the paper surface hair; 7
8 indicates a magnetic bubble transfer section, 8 indicates a magnetic bubble extension section, and 10 indicates two conductor layers 3 and 4 on the magnetic thin film.

A large number of patterned holes, for example 11, indicated by dotted lines are provided in the first conductor layer, and a large number of patterned holes, for example 12, indicated by solid lines are provided in the second conductive layer. As shown in FIG. 1a, the positions of the pattern holes in the first conductor layer and the positions of the pattern holes in the second conductor layer are slightly shifted from each other. 13 and 15 indicate the direction of current flowing through the first conductor layer 3, and 14 and 16 indicate the direction of current flowing through the second conductor layer 4.

17 to 22 indicate transfer positions (hereinafter referred to as positions) of magnetic bubbles (hereinafter referred to as bubbles) in pattern holes.

For example, if the first conductor layer 3 is energized in the direction of the arrow 15, an induced magnetic field is generated near the position 18 in the pattern hole in the opposite direction to the bias magnetic field 6 due to the current, which acts to weaken the bias magnetic field 6. , the baffle is still attracted to position 18.

On the other hand, near the positions 17 and 20, the bias magnetic field 6 is strengthened, so that the bubbles are repulsed. The combination of this suction and anti-travel causes the bubble to remain at position 18. Then the second
When the conductor layer 4 is energized in the direction of the arrow 16, bubbles are attracted and transferred to transfer positions 19 in the pattern holes. Next, the first
When the conductor layer 3 is energized in the direction of the arrow 13, the position 20' is
Next, when the second conductor layer 4 is energized in the direction of the arrow 14, the position 2
The bubble is transferred to 1. Once again, mark the arrow 1 on the first conductor layer 3.
5, the bubble is transferred to position 22. That is,
One bit of bubble was transferred. By sequentially repeating this process, the bubbles are sequentially transferred to the transfer positions of the pattern holes. By the way, in the conventional magnetic bubble extension pattern, the induced magnetic field is concentrated at the pattern end of the magnetic bubble extension part 8. Figures 2a and b show how the bubble transferred from the transfer unit 7 expands in the magnetic bubble extension unit 8 and the magnetic field potential.
In FIG. 2a shown in FIG. , FIG. 2b shows the magnetic field potential curve of FIG. 2a, where 26 is the magnetic field potential axis, 27 is the distance in the short side direction of the elongated pattern hole 24, and 28 is the drive current 15.
This is the magnetic field potential curve generated by As shown by a curve 28, the magnetic field gradient becomes smaller at the center 29 of the pattern hole, and the bottom of the potential becomes deeper at the periphery of the pattern hole.
Therefore, the expanded bubble is difficult to be transferred. Furthermore, the strength of the magnetic field that weakens the bias at both ends 30a and 30b of the pattern hole 24 is due to a slight difference in the magnetic field at both ends.
Once expanded, the bubble returns to a bubble state closer to one end, or expands again at the next pattern hole. That is, the normal bubble state and the extended bubble state may be repeatedly transferred. In the process, one elongated bubble may separate and two bubbles may be generated at both ends of the pattern hole (for example, 30a, 30b, etc.). For example, the perm of the thin film magnetoresistive detection section 2 (hereinafter referred to as the detection section). On the magnetoresistive pattern consisting of the bubbles, the bubbles elongate, but if they remain elongated, the adsorption force to the permalloy is strong, so if only the driving currents 13, 14, 15, and 16 are used, the elongated bubbles will not move to the next pattern position. It is difficult for the signal to be transferred to the detector 2, and it often stops at the correct position of the detection unit 2. As described above, the conventional method has a very narrow operating range as a magnetic bubble detector and is not suitable for practical use.

In order to overcome these drawbacks of the prior art, the present invention combines a hairpin-like conductor and a thin film magnetoresistive detector into a transfer pattern, and will be described in detail below with reference to the drawings.

FIG. 3a shows a plan view of the two-layer conductor current-driven magnetic bubble device of the present invention, and FIG. show.

Figure 3a "In Figure 3b, the same parts as in Figures 1a and 1b are given the same numbers. 1 is a magnetic thin film for magnetic bubbles such as garnet, and 2 is a high permeability thin film such as permalloy. a magnetoresistive detection section; 31 is a hairpin-shaped conductor; 3 is a first conductor layer;
4 is a second conductor layer, and an insulating layer 5 of SiO2 or the like is arranged between each layer.

Figure 3a shows its plan view. Reference numeral 2 indicates a thin film magnetoresistive detection section (hereinafter referred to as the detection section), 31 indicates a hairpin-shaped conductor, and one or two conductor layers.

A number of patterned holes, for example 11, indicated by dotted lines are provided in the first conductor layer, and a number of patterned holes, for example 12, indicated by solid lines are provided in the second conductor layer. Furthermore, the bubble driving principle and the like are completely the same as the conventional one. An important point is that the elongated rectangular pattern holes (eg 24) are not used to extend the magnetic bubbles as in the case of a follower. That is, a pattern hole having the same shape as that of the transfer section 7 is used in the extension section 8 as well, and the detection section 2 made of permalloy or the like is arranged so as to overlap this at the end. Furthermore, a hairpin-shaped conductor 31 is arranged so as to surround this detection section 2. By using these three in combination, the extensibility and transferability of the magnetic bubble in the detection section 2 of the two-layer conductor current-driven magnetic bubble device are greatly improved. The positional relationship between the bent portion of the hairpin-shaped conductor 31 and the pattern hole of the extension portion 8 is set at such a position that a particularly strong induced magnetic field near the bent portion of the hairpin-shaped conductor 31 does not have any influence. First, as described in the explanation of the prior art, the bubble drive current is energized 15, 16, 13.
, 14 and the positions 34, 35, 36, 37, in the pattern holes.
Bubble transfer is performed in the order of 38. Further, when the bubble is transferred to the position of the pattern hole 39, an elongating current is applied to the hairpin-shaped conductor 31 in the direction of the arrow X in timing with the drive current pulse. Hair hee. The bias magnetic field 6 is weakened inside the hairpin-shaped conductor 31, and the bubble tends to expand inside the hairpin-shaped conductor 31. In other words, the bubble is detected by the detection unit 2.
Stretch to the same shape as the top of. Since the bias magnetic field 6 is strengthened outside the hairpin-shaped conductor 31, the bubble protrudes beyond the hairpin-shaped conductor 31. The presence or absence of a bubble is detected by the change in magnetoresistance of the Permalloy thin film due to the elongated bubble. After the bubble is detected, the hairpin-shaped conductor 31 is energized in the Y direction opposite to the arrow X to contract the bubble.

The bias magnetic field 6 inside the hairpin-shaped conductor 31 is strengthened, and the elongated bubble tends to contract. At this time, drive current 16
, 13, the bias magnetic field 6 is weakened near the pattern holes 39, 40. Therefore, in the permalloy thin film of the detection section 2, the bias magnetic field 6 is strong on the left side 43 and weak on the right side 44, creating a magnetic field gradient in the left and right directions. Therefore, the bubble tends to contract toward the right side of the detection section 32, that is, the bubble contracts near the transfer pattern hole 40. The bubble does not jump out from the transfer path and remains at position 401. FIG. 4 shows the strength of the magnetic field in the detection unit 2 in this state using a potential curve. 45
is the magnetic field potential, 46 is the distance in the direction of the edge of the detection unit 2, and 47 is the hairpin-shaped conductor 31 to contract the bubble.
48 is an induced magnetic field potential curve caused by applying current to the first conductor layer 3 or the second conductor layer 4, and 49 is a composite potential curve of both of them. .

When a high magnetic permeability material is used for the detecting section 2 in this way, the detecting section itself is magnetized and the composite potential has a magnetic field gradient as shown in FIG. That is, the transfer path pattern 39
, 40 has the smallest potential. Also,
Since the bias magnetic field becomes weak in the vicinity of 39 and 40, the elongated bubble contracts at the transfer path pattern hole 40. When the elongated bubble contracts into a bubble shape, the adsorption force to the permalloy of the detection part 2 becomes weaker, and the drive current 16, 13, 14
, 15 is sufficient for transfer. In other words, the bubbles do not remain at the detection unit position as in the past, but instead
, 41, 42. FIG. 5 shows the timing sequence of driving current and energization of the hairpin-shaped conductor 31 for bubble expansion. In Figure 5,
5. Current axis, 51 is time axis, 52, 53 is energization 15, 13 to the first conductor layer, 54, 55 is energization 16, 14 to the second conductor layer, 56 is for magnetic bubble expansion. 57 shows the energization X to the hairpin-shaped conductor 31, and conversely, 57 shows the energization Y to the hairpin-shaped conductor 31 for contraction of the elongated bubble.

As explained above, by using the present invention, the transferability of bubbles at the detection unit is improved, and the bubbles can be expanded and contracted extremely smoothly.

In addition, there is no drawback that bubbles jump out of the transfer pattern or that two bubbles are generated from one extended bubble and transferred. FIG. 6 shows a second embodiment of the present invention, in which the hairpin-shaped conductor 31 has a shape in which the spacing between opposing inner sides is widened on the right side (the side with the transfer pattern) 58 and narrowed on the left side 59. This allows for smooth bubble expansion and contraction.

That is, by providing width on the inside of the hairpin-shaped conductor, a magnetic field gradient is generated in the direction of the outermost side of the detection section 2. When the magnetic bubble expands, the spacing on the left side 59 of the hairpin-shaped conductor 31 is narrower than on the right side 58, so a stronger magnetic field is generated in the direction of the anti-bias magnetic field, making it easier for the baffle to expand to the left. On the other hand, when the magnetic bubble contracts, the hairpin-shaped conductor 3
Since a stronger magnetic field is generated in the direction of the bias magnetic field on the left side 59 of 1 than on the right side 58, the elongated bubbles tend to contract to the right, forming a bubble shape on the transfer path pattern. As explained above, in a two-layer conductor current-driven magnetic bubble device, there is a detection section consisting of an elongated rectangle that partially overlaps the transfer pattern hole, and a hairpin-shaped sensor for bubble extension surrounding the detection section. By placing it in combination with a conductor, it is possible to expand and contract the bubble extremely smoothly.
Furthermore, bubble transfer in the detection unit is also easy.

The present invention provides a current-driven, high-speed, high-density, low-power, two-layer conductor current-driven magnetic bubble device. The present invention has a two-layer conductor current-driven magnetic bubble diagonal that has a thin film magnetoresistive detection section and a hairpin-shaped conductor surrounding it, so that accurate bubble expansion, contraction, and good transfer can be achieved. It has advantages such as performance, and can realize a high-speed, high-capacity two-layer conductor current-driven magnetic bubble device.

[Brief explanation of the drawing]

Figures 1a and 1b are a plan view and layer sectional view of a conventional two-layer conductor current-driven magnetic bubble device, and Figures 2a and 2b are
is an explanatory diagram of the magnetic field potential in a conventional magnetic bubble device,
3a and 3b are a plan view and a layer sectional view of a two-layer conductor current-driven magnetic bubble device of the present invention, and FIG. 4 is an explanatory diagram of the magnetic field potential in the magnetic bubble device of the present invention. FIG. 5 is an explanatory diagram of the timing sequence of driving current and energization to the hairpin-shaped conductor for bubble expansion in the magnetic bubble device of the present invention, and FIG. 6 is a diagram showing a second embodiment of the present invention. Figure l Figure '01 Figure 2 Figure 4 Figure 3 Figure '01 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. Two conductor layers forming a pair to form a magnetic bubble transfer path, each layer of which is provided with a patterned hole serving as a magnetic bubble transfer path, and the two conductor layers forming a pair to form a magnetic bubble transfer path. In a magnetic bubble device comprising an insulating layer interposed between the layers and a thin film magnetoresistive detector disposed at a position that partially overlaps the transfer path in a plane with the insulating layer interposed, the thin film magnetoresistive detector A magnetic bubble device comprising a hairpin-shaped conductor disposed around the conductor layer and insulated from the thin film magnetoresistive detection section. 2. Claim 2, characterized in that the hairpin-shaped conductor has a hairpin shape in which the distance on the inside of the bent portion is wide, and the distance on the inside opposite to the bent portion is narrowed. The magnetic bubble device according to item 1.