JPS5856185B2 - magnetic bubble expander - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble storage element using magnetic bubbles (hereinafter abbreviated as bubbles) for storage, and a bubble detection device in which a bubble expansion circuit and a bubble detection circuit are simultaneously formed. The present invention relates to an expanding device, and particularly to a magnetic bubble expanding device that has improved operating margins and high-speed operation characteristics for bubble expansion and transfer.

As shown in FIG. 1, a conventional magnetic bubble expansion device has a large number of chevron-shaped bubble transfer elements 1 formed of a soft ferromagnetic thin film several thousand angstroms thick arranged in a direction perpendicular to the bubble traveling direction 12. In the evening, I used a bubble expander (
(hereinafter simply referred to as expander) 2 to 10 in the bubble traveling direction 12
expanders 2 to 10 so that the bubble 13 can be expanded sequentially.
The number of stages of chevron-shaped bubble transfer elements 1 arranged in a direction perpendicular to the bubble traveling direction 12 is increased sequentially with respect to the bubble traveling direction 12, and the presence or absence of bubbles 13 is detected by a bubble detector 11 using a magnetoresistive effect. The bubble 13 is stretched 100 times as much as shown in the figure until it can be recognized as an electrical signal, and the string-shaped bubbles 14 to 16 are then transferred in the bubble traveling direction 12.

The bubble expanding device configured in this manner is required to have good characteristics of expanding the bubble 13 in a direction perpendicular to the bubble traveling direction 12 and simultaneously transferring it in the bubble traveling direction 12.

However, in the transfer characteristics of the bubble expansion device shown in Figure 1, the operating margin deteriorates on the low bias magnetic field side, and it was observed that normal bubble transfer does not occur at low drive magnetic fields Hr, so-called abnormal transfer. .

It has been found that as the drive frequency increases, the probability of this abnormal phenomenon occurring increases and the deterioration of the transfer characteristics is also significant.

As mentioned above, in the conventional magnetic bubble expansion device, an abnormal phenomenon occurs and the transfer characteristics deteriorate, and as the driving frequency increases, the transfer characteristics deteriorates significantly and the characteristics of the magnetic bubble storage element deteriorate. It has the disadvantage of causing

As a result of a detailed study of the above-mentioned abnormal phenomenon, it was found that this abnormal phenomenon is caused by the expanded string-shaped bubbles 14 to 16 being divided into two or more while being transferred to the bubble detector 11, and after reaching the normal bubble position. It was found that this was due to the generation of new string-like bubbles that were split.

It has been found that this bubble splitting phenomenon occurs during the transfer of the expanders 2 to 10 that sequentially expand the bubble 13.

FIG. 2 is an explanatory diagram showing this abnormal phenomenon.

The string-like expanded bubble 20 must be transferred from one expander 18 to the next expander 19 with each rotation of the driving field.

However, as shown in FIG. 2a, in the part of the expander 18 where the number of stages is larger than that of the expander 17 in the front row, the stray magnetic field that the chevron-shaped bubble transfer element 1 receives from the driving magnetic field is due to the fact that the chevron-shaped bubble transfer element 1 is not in the front row. Small and weak bubble suction or repulsion power, i.e. string-like bubbles 2
Since the force for transferring 0 is weak, a larger 1 driving magnetic field is required compared to the part where the chevron-shaped bubble transfer element 1 is located in the front row.

Therefore, on the low 1 drive magnetic field side, the string-shaped bubbles 201 in the portion where the chevron-shaped bubble transfer element 1 is present in the front row expander 17 in FIG. 2a are transferred to the next row expander 19, whereas The string-like bubble 202 in the part where the chevron-shaped bubble transfer element is not present in the expander 17 may not be transferred and may remain in the expander 18, and the string-like bubble 20 may be separated into two parts as shown in FIG. Magnifier 18゜1
If the driving magnetic field further rotates, the bubble will be split into two, and independent bubbles 21 and 22 will be generated in the expander 18 and the expander 19, respectively.

As a result, normal bubble detection is not performed.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic bubble expanding device that does not cause abnormal phenomena and has excellent transfer characteristics even when the driving magnetic field is low and the driving frequency is high. A magnetic device that expands magnetic bubbles in a direction perpendicular to the direction of travel by stacking a large number of magnetic bubble expander elements made of soft ferromagnetic thin films on a magnetic thin film to be obtained at a constant repetition rate in a direction perpendicular to the direction of travel of the magnetic bubbles. A magnetic bubble expanding device comprising a bubble expander, arranging a large number of bubble expanders at a constant period in a magnetic bubble traveling direction to expand magnetic bubbles in a direction perpendicular to the traveling direction and transferring them in the traveling direction, Expanding the magnetic bubble step by step from a first magnetic bubble expander that receives and receives the magnetic bubble from the magnetic bubble transfer path to an n-th magnetic bubble expander having a final expansion length by sequentially increasing the expander elements. In the magnetic bubble expanding device, a dummy expander is provided, in which a large number of the expander elements or similar expander elements are stacked at a constant repetition period with an interval of at least one repetition period of the expander elements. , the first to n-1th magnetic bubble expanders are arranged in both directions or only in one direction of the stacking direction of the expander elements.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a conceptual diagram showing an embodiment of the magnetic bubble expansion device according to the present invention.

The figure includes a bubble transfer path section 23, an expander group 24, a bubble detector section 25, and a dummy expander group 26.

The dummy expander group 26 does not work to expand bubbles, but to assist in the transfer of so-called string-like bubbles, and this dummy expander group 26 eliminates abnormal transfer.

The dummy expander elements are comprised of expander elements, and the bubble expanders and the dummy expanders are spaced apart such that at least one bubble expander element can be disposed therebetween.

FIG. 4 is a diagram illustrating a main part of an embodiment of a magnetic bubble expanding device according to the present invention.

This figure is a conceptual diagram showing an embodiment of the magnetic bubble expanding device according to the present invention shown in FIG.
These are dummy enlargers 27-29.

According to the magnetic bubble expansion device configured in this way, the bubbles expanded by the bubble expansion devices 17 to 19 in a direction perpendicular to the bubble transfer direction increase the number of stages of expansion elements for sequential expansion. A large stray magnetic field is also applied to the part where the data is transferred, so that the data can be transferred normally.

In other words, the abnormal phenomenon explained in FIG. 2 is greatly reduced in FIG. 4, and the transfer characteristics on the low driving magnetic field side are improved.

Further, normal transfer can be performed even when the driving frequency is increased.

FIG. 5 shows the operational margin of transfer of the magnetic bubble expansion device in the case of the conventional configuration (curve ■) and in the case of the embodiment of the present invention shown in FIG. 4 (curve ■). .

The illustrated operating margin was measured at a drive frequency of 200 KHz.

In this case, the bubble medium is (YSmLuCa)3(FeG
e) 5012, the constants of the medium are a magnetic domain width of 1.8 μm, a saturation magnetization of 400 G, and a bubble extinction/demagnetization field of 2200 e.

As is clear from the figure, the magnetic bubble expansion device according to the present invention has significantly improved characteristics on the low driving magnetic field side compared to the conventional device.

It goes without saying that the present invention is not limited to these embodiments, and that the effects of the present embodiments can be expected for magnetic bubble expansion devices having any expansion element.

It goes without saying that the same effect as described above can be obtained even when the enlarger element is combined with a dummy enlarger element having a different shape.

As explained above, according to the magnetic bubble expansion device according to the present invention, it is possible to obtain a large margin of operation for transfer in a low driving magnetic field region and excellent high-speed operation characteristics.

Furthermore, the magnetic bubble expansion device according to the present invention minimizes fluctuations in operating margin due to fluctuations in bubble medium characteristics, magnetic bubble storage element manufacturing conditions, etc., and improves the manufacturing yield of magnetic bubble storage elements. .

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of main parts showing an example of a conventional magnetic bubble expansion device, Fig. 2 is an explanatory diagram of an abnormal phenomenon in a conventional magnetic bubble expansion device, and Fig. 3 is a conceptual diagram of an embodiment of the device of the present invention. , FIG. 4 is a configuration diagram of a main part of an embodiment of the device of the present invention, and FIG. 5 is a driving magnetic field Oe-bias magnetic field Oe characteristic showing an example of the measurement results of the operating margin of the conventional magnetic bubble expansion device and the present invention. It is a curve diagram. 1...Chevron-shaped bubble transfer element, 2-10
... Bubble expander, 11 ... Bubble detector, 12 ... Bubble execution force direction, 13 ...
... Bubble, 14-16 ... String bubble, 1
7-19... Bubble expander, 20-22...
... String bubble, 23 ... Bubble transfer path section, 24 ... Bubble expander group, 25 ...
Bubble detector section, 26...Dummy magnifier group, 2
7-29...Dummy magnifier.

Claims (1)

[Claims] 1. By stacking a large number of magnetic bubble expander elements made of soft ferromagnetic thin films on a magnetic thin film capable of holding magnetic bubbles at a constant repetition rate in a direction perpendicular to the direction of magnetic bubble travel, magnetic bubbles are expanded in the direction of travel. A magnetic bubble expander that expands in a perpendicular direction is configured, and a large number of the bubble expanders are arranged at a constant period in the direction of travel of the magnetic bubble to expand the magnetic bubble in the direction perpendicular to the direction of travel and transfer it in the direction of travel. a first magnetic bubble expander that receives and receives magnetic bubbles from a magnetic bubble transfer path, and successively increases the expander elements up to an nth magnetic bubble expander having a final expansion length; In a magnetic bubble expansion device for expanding a magnetic bubble stepwise, a plurality of the expansion elements or similar expansion elements are stacked at intervals of at least one repetition period of the expansion elements at a constant repetition period. A magnetic bubble expanding device characterized in that dummy expanders stacked in the above are disposed in both directions or only in one direction of the stacking direction of the expander elements of the first to ni-th magnetic bubble expanders.