JPH0544754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic bubble generator in a memory device that uses magnetic bubbles as information carriers. More specifically, the present invention relates to a magnetic bubble generator that nucleates magnetic bubbles using a local magnetic field generated by applying a current pulse to a conductor pattern.

(Prior art and its problems) Magnetic bubble memory devices that use magnetic valves as information carriers use a magnetic bubble generator that generates magnetic bubbles depending on the presence or absence of information, or a magnetic bubble generator that transfers the generated magnetic bubbles to a predetermined position. The magnetic bubble transfer path is the most important functional element. Recent magnetic bubble generators are, for example, developed by T.G. Nelson (T.J.
In 1980, Nelson et al.
Technical Journal (The Bell System)
As shown on pages 229 to 257 of vol. 29. No. 2 (Technical Journal) vol. 29. No. 2, the magnetization in the magnetic bubble transfer path made of connected circular patterns of ion implantation tends to concentrate in a specific direction of the rotating magnetic field. It has a shape in which a hairpin-like conductor pattern is arranged, and magnetic bubbles are generated by the sum of the local magnetic field generated by applying a current pulse to the hairpin-like conductor and the local magnetic field from concentrated magnetization. ing.

On the other hand, when applying a current pulse to such a hairpin-shaped conductor, Japanese Patent Publication No. 57-36669 discloses that a heat dissipation fin is provided at the tip of the hairpin conductor in order to reduce the effect of heat generation on the hairpin conductor due to the current. It is stated inside. An example of applying this to a magnetic bubble generator was published by REFontana et al. in 1980 in IEEE Transactions on Magnetics (IEEE.Trans.onMagn. ) No. MAG
It is shown in FIG. 15 of No.-16, pages 1101 to 1105. The conventional NuCreation type magnetic bubble generator using a hairpin conductor pattern with heat dissipation fins has the following problems.

The problems of the conventional magnetic bubble generator will be explained using FIG. Here, as a conventional example, the above-mentioned
The magnetic bubble transfer path made of permalloy by Fontana will be explained by replacing it with the ion implantation transfer pattern 1 by Nelson. Even if the transfer pattern is replaced in this way, there is no essential difference in explaining the problem. The hairpin-shaped conductor pattern 2 for generating nucleation of magnetic bubbles has a heat radiation fin 20 having a large area at its tip. Furthermore,
This hairpin-shaped conductor pattern has a gap 21
are arranged so as to overlap with the connecting cusp portion 10 of the connecting circular pattern 1 where magnetization is strongly concentrated in a predetermined direction of the in-plane rotating magnetic field H _R shown by 4.

When generating magnetic bubbles, a current pulse 3 is applied to the hairpin-shaped conductor pattern 2. The current pulse flows in the conductor pattern as shown by the arrow 31, and at the tip of the hairpin conductor where the heat dissipation fin is located, the current pulse follows a short current path as shown by the arrow 32 near the gap 21, and in the area far from the gap 21, the current pulse follows a short current path as shown by the arrow 32. As the temperature increases, the flow is distributed within the heat dissipation fin as shown by the arrow 33. The current component flowing through the heat dissipation fins is farther away than the conductor gap 21 and the overlapping part of the connecting cusp part 10 where the magnetization of the magnetic bubble transfer pattern is concentrated, so it substantially makes almost no contribution to the generated magnetic field. .
In other words, although a strong magnetic field is required to generate nucleation of magnetic bubbles by current pulses, due to the presence of the heat dissipation fins, current components that do not substantially contribute to the generated magnetic field are distributed within the heat dissipation fins. Therefore, the magnetic field generation efficiency of the applied current pulse decreases. That is, in such a conventional example, a large current pulse is required to generate a magnetic bubble.

(Object of the Invention) The object of the present invention is to eliminate such conventional drawbacks and provide a magnetic bubble generator having a hairpin-like conductor pattern with heat dissipation fins that has good magnetic field generation efficiency and does not reduce the heat dissipation effect. It's about doing.
Furthermore, by using the present invention, it is possible to provide a magnetic bubble generator with fewer malfunctions.

(Structure of the Invention) According to the present invention, in a nucleation type magnetic bubble generator in which a conductor pattern is arranged in the magnetization concentrated part of a magnetic bubble transfer path provided on a thin piece of magnetic material capable of holding magnetic bubbles, A magnetic bubble generator is obtained, characterized in that the conductor pattern is provided with a slot.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-described configuration. The principle of the present invention is that when a conductor pattern has an elongated groove-like non-conductor part (hereinafter referred to as a slot), when a current is applied to that conductor, the current cannot flow through that part due to the presence of the slot. This is due to the fact that the distribution of the magnetic field generated by the current flowing around it changes significantly due to the presence of the slot. On the other hand, in the longitudinal direction of the rectangular slot in the conductor, there is almost no change in heat conduction within the conductor depending on the presence or absence of the slot. Based on the above two principles, the present invention makes it possible to create a conductor pattern that achieves both a heat dissipation effect and an efficient magnetic field generation effect.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Example 1 A first example of the present invention will be described with reference to FIG.

In explaining this embodiment, the presence of the magnetic material thin piece that holds the magnetic bubbles and the magnetic bubble transfer pattern are not essential, and therefore will not be described here. The hairpin-shaped conductor pattern 2 for generating magnetic bubbles has a rectangular heat dissipating fin 20 at its tip, and a rectangular slot (opening) is formed approximately in the center of the heat dissipating fin 20 in a direction substantially parallel to the hairpin gap 21. hole) 22 is provided. A current pulse is applied to this hairpin-shaped conductor 2 in the direction shown by arrow 3.
All of this current pulse flows through the arm portion of the hairpin-shaped conductor as shown at 31. In the heat dissipation fin section 20, this current cannot be freely distributed within the fin due to the presence of the slot 22, and most of it is
As shown in FIG. 2, it passes through the part between the slot 21 and the hairpin gap (near the slot end 22). Then, as shown in only a small portion 33, another slot end 22b of the slot pattern 22
flowing nearby. This current component 33 can be almost ignored if the slot is long enough, and if the slot is extended to the outer periphery of the heat dissipation fin 20 and formed into a notch shape that is connected to the outside, the current component 33 does not exist at all. (Dotted line in FIG. 2) As described above, due to the presence of the slot, the current component indicated by 32 is extremely large, and therefore the local magnetic field generated in the hairpin gap 21 is also large. In other words, the amplitude of the current pulse that generates a constant local magnetic field necessary for generating nucleation of magnetic bubbles may be small.

On the other hand, the Joule heat generated by applying a current pulse to such a hairpin-shaped conductor pattern becomes maximum near the tip of the hairpin gap. On the other hand, as described above, almost no current flows through the heat dissipation fins 20, and the generation of Joule heat can be almost ignored in this part, and the temperature is kept low.
Therefore, the flow of heat is parallel to the longitudinal direction of the slot from between the hairpin gap 21 and the slot end 22a, and the presence of the slot has almost no effect on the flow of heat, as described above. . That is, it means that the heat dissipation effect is not impaired in any way.

Therefore, by using the hairpin conductor pattern of this embodiment, a magnetic bubble generator can be easily realized which can be driven with a current pulse having a smaller current amplitude and which has good heat dissipation, resulting in less temperature rise.

Example 2 FIG. 3 shows a second embodiment of the invention.

The shape of the heat dissipation fin 20 of the hairpin-shaped conductor pattern 2 of this embodiment has a large number of comb-shaped protrusions 2 on its three sides.
0a is provided to improve the heat dissipation effect.
A slot 22 is provided in the center of the heat dissipation fin 20, substantially parallel to the hairpin gap 21, as in the first embodiment. However, the effect on the current pulse is similar to that of the first embodiment already described.

Embodiment 3 FIG. 4 is a diagram showing a third embodiment of the present invention.

The purpose of this embodiment is slightly different from that of the previous two embodiments; a plurality of slots 22, 23, 24, and 25 are provided in the conductor pattern 2 for the purpose of reducing malfunctions of the magnetic bubble generator. be. A conductive pattern is provided in the cusp portion 10 where the magnetization of the magnetic bubble transfer pattern 1 is concentrated so that the slot end 23a of the first slot 23 is located. The second slot 22 extends in the same direction as the first slot, and has a slot end 22a and a first slot 23.
The slot ends 23a of the two are opposite to each other. slot 2
Wide slots 24, 25 on both sides of 2, 23
are lined up on both sides of the opposing portion of the slot ends 22a and 23a.

When a magnetic bubble is generated, a current pulse 3 is applied to this conductor pattern 2. With this kind of slot arrangement, there are many current paths, but the slot end 2
If the conductor pattern width near 3b is narrowed, most of the current pulse will flow in the solid line arrow 31 in the figure, and only a small amount of current will flow in the path indicated by the broken line arrow 33 and other paths. As a result, a strong magnetic bubble generating magnetic field is generated at the slot end 23a, and the slot end 22a, 2
3b has a magnetic field of opposite polarity, and 22b has a magnetic field of opposite polarity.
Although it has the same polarity as 3a, an extremely weak magnetic field is generated.

Therefore, the magnetic bubble is nucleated in the cusp portion 10 due to the weak magnetic field component of the slot 23 in the generation direction. At this time, in the slot 23,
23b has a magnetic field of opposite polarity, and 2 outside the slot.
Since a magnetic field of opposite polarity is generated at the slot 2a, the generated magnetic bubble can exist only in the vicinity of the slot end 23a. In this regard, in the case of the conventional example shown in Fig. 1, when a magnetic bubble is generated, the hairpin gap 2
In No. 1, a magnetic field of the same polarity as the bubble generation is generated all over, and the generated magnetic bubbles extend randomly within the gap 21, which has the disadvantage of causing magnetic bubble generation malfunction. In this embodiment, such a malfunction is impossible because the generated magnetic bubble can exist only at the slot end 23a.

(Effects of the Invention) As described above, by using the present invention, the amplitude of the current pulse for generating magnetic bubbles can be reduced, and a magnetic bubble generator with good current effect can be realized. Furthermore, by using the present invention, a magnetic bubble generator with fewer magnetic bubble generation malfunctions can be realized.
Further, although the present invention has been explained using an ion implantation pattern as a magnetic bubble transfer pattern, the present invention can be applied even if this is a permalloy pattern or a perforated two-layer conductor pattern. Needless to say.

[Brief explanation of the drawing]

Figure 1 shows a conventional bubble generator, Figure 2 shows a conventional bubble generator.
3, and 4 are diagrams showing embodiments of the bubble generator of the present invention, respectively. In the figure, 1 is a transfer pattern, 2 is a conductor pattern, 3 is a current pulse, 4 is an in-plane rotating magnetic field, 10
is a cusp portion where magnetization is concentrated, 11 is a magnetic bubble transfer path, 20 is a conductor pattern for heat radiation, 20a is a protrusion pattern for heat radiation, 21 is a hairpin gap portion, 22,
23, 24, 25 are slot patterns, 22a, 2
2b, 23a, 23b are slot ends, 31, 3
2 and 33 indicate arrows indicating the path of the current pulse.

Claims (1)

[Claims] 1. In a nucleation type magnetic bubble generator in which a conductor pattern is arranged in the magnetization concentrated part of a magnetic bubble transfer path provided on a thin piece of magnetic material capable of holding magnetic bubbles, a slot is provided inside the conductor pattern. A magnetic bubble generator characterized by: