JPS6134637Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a shape of a propagation pattern hole that can reduce the driving current in a magnetic bubble element using a multilayer conductor sheet type current driving method.

(Background Art) Details of the drive principle and method of the current-driven magnetic bubble element, which is directly related to the present invention, can be found in the literature (The Bell System Technical Journal Vol. 58,
No. 6, 1453'79). Conventionally, the shape of the holes in the pattern of the first conductor layer and the shape of the holes in the pattern of the second conductor layer were exactly the same.

FIG. 1 shows the layer structure in a conventional device. 1 is a magnetic film for magnetic bubbles such as garnet, 2 is a first conductor sheet layer, 3 is a second conductor sheet layer, 4 is SiO ₂
It is an insulating layer such as. Reference numeral 5 indicates an opening pattern formed in the first conductor layer, and 6 indicates an opening pattern formed in the second conductor layer. FIG. 2 shows a plan view of the device. 11
1 shows the first and second conductive sheet layers laminated on the magnetic film 1. Patterns shown in solid lines, e.g. 16
is perforated in the second conductive sheet, and the pattern shown by broken lines, for example, 17, is perforated in the first conductive sheet. The combination of these two aperture patterns constitutes 1 bit, and a large number of them are arranged. 10 indicates the direction in which the bias magnetic field is applied.
20 and 21 indicate the current direction to the first conductor sheet;
2 and 23 indicate the direction in which electricity is applied to the second conductive sheet.
When energized 20, the magnetic bubble 15 moves to the opening pattern end 25.
Then, energization 22 is applied to the opening pattern end 26, and further 21
The magnetic bubble 15 is propagated to 27 at 27 and 28 at 23, and further propagated to the next aperture pattern end 29 by energization 20, where 1 bit is transferred. In this method, the pattern holes 17 in the first conductive sheet layer and the pattern holes 16 in the second conductive sheet layer are completely identical. Therefore, in order to obtain a magnetic field induced by the pattern 16 in the second layer, which is located away from the magnetic film 1, to be equal to the value caused by the pattern 17 in the first layer, the driving current density should be approximately twice that of the driving current density to the first layer. Requires. In other words, in a multilayer structure, the current efficiency decreases as the layer increases. The higher the layer, the more the drive current increases, causing the problem of heat generation in the conductor sheet.
Furthermore, it becomes difficult to manufacture a large current driver. For example, for the propagation of a 2 μm bubble, the entire bubble element requires several A
This is a serious problem for electronic devices.

(Problem for the invention) The purpose of the invention is to improve the above-mentioned drawbacks of the conventional technology.The feature is that a plurality of conductive sheet layers having an opening pattern for bubble propagation are formed on a magnetic film for magnetic bubbles as an insulating layer. In a current-driven magnetic bubble element having an overlapping structure with the conductive sheet layer separated from the magnetic film, the opening pattern in the conductive sheet layer farther from the magnetic film is larger than the opening pattern in the conductive sheet layer closer to the magnetic film.

(Structure and operation of the invention) The cross-sectional view of the bubble element layer structure of the invention is the same as the conventional one. In this description, a two-layer structure will be described, but a multi-layer structure is also equivalent. FIG. 3 shows a plan view of the device of the present invention. Similarly to the prior art, reference numeral 11 indicates first and second conductor sheet layers laminated on the bubble magnetic film. A pattern shown by a broken line, for example 31, is perforated in the first conductive sheet, and a pattern shown by a solid line, for example 32, is perforated in the second conductive sheet. The difference from the prior art is that the pattern 32 is larger than the pattern 31. That is, the farther the conductive sheet layer is from the bubble magnetic film, the larger the pattern shape of that layer becomes. This increases the induced magnetic field relative to the drive current density and improves current efficiency. The principle method for propagating bubbles is exactly the same as in the prior art. FIG. 4 shows the state of the induced magnetic field depending on the size of the pattern hole shape. Reference numeral 41 indicates the distance from the bubble magnetic film, and 42 indicates the perpendicular component of the induced magnetic field, respectively, on an arbitrary scale. 43 is for example
The cell area of 1 bit is (8×8) μm ² and the pattern hole is a rectangle of (2×4) μm ² . On the other hand, the cell area 44 is the same as the cell area 43, but the pattern hole is (3
×5) It is a rectangle of μm ² . In this case, by making the pattern holes larger, the induced magnetic field per unit current can be reduced to approximately
Increase by 60%. In other words, although the induced magnetic field decreases with distance, it has been shown that this decrease can be alleviated by gradually enlarging the pattern holes, indicating that this is an extremely effective method. Therefore, in the current drive method using a conductor sheet, an effective method for increasing the drive current efficiency is to gradually enlarge the pattern holes in the conductor layer that are farther away from the magnetic film. In particular, it is extremely effective for current driving methods using feedback type conductor sheets using a multilayer structure. However, in the present invention, since the pattern hole becomes larger, the resistance of the conductor layer naturally increases.
Although the drive current is reduced, the resistance increases, so it is important to compare the power consumption. In the case of the example in Figure 4, comparing the power consumption to obtain the same induced magnetic field,
P ₄₃ /P ₄₄ ≈1.5, and it is advantageous to make the pattern larger in terms of power consumption as well.

As explained above, in a conductor sheet pole current-driven magnetic bubble element having a two-layer or multilayer structure, it is effective to make the pattern holes drilled in the conductor sheet farther away from the bubble magnetic film gradually larger. However, this should be considered within a range that does not increase power consumption. By using the present invention, the driving current is reduced and the manufacturing of the driver is also advantageous.

(Effects of the invention) The present invention relates to the shape of pattern holes with high drive current efficiency, and has the advantage of low drive current, and can be used in high-speed current-driven magnetic bubble memories.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic bubble element, FIG. 2 is a plan view of pattern holes in the first and second conductor layers of the conventional element, and FIG. 3 is a plan view of pattern holes in the first and second conductor layers of the element of the present invention. The plan view of FIG. 4 is a diagram showing changes in the induced magnetic field depending on the size of the pattern hole.

Claims (1)

[Scope of utility model registration request] In a current-driven magnetic bubble element that has a structure in which multiple conductor sheet layers each having an aperture pattern for bubble propagation are stacked on a magnetic film for magnetic bubbles with an insulating layer interposed therebetween, the aperture pattern in the conductor sheet layer far from the magnetic film A magnetic bubble element characterized in that the opening pattern is larger than the opening pattern of a conductive sheet layer close to the magnetic film.