JPS6344397A - Bubble generator for magnetic bubble memory - Google Patents

Abstract

PURPOSE:To obtain a bubble generator generating magnetic bubbles, which has a low current value and less power consumption by using an exothermic resistance as a conductive pattern generating a partial magnetic field which generates magnetic bubbles on a magnetic thin film. CONSTITUTION:A hair pin-like exothermic resistance pattern 5 made of HfB2, etc., is additionally provided on a magnetic garnet thin film 4 as the conductive pattern generating the partial magnetic field generating magnetic bubbles, and wiring conductive patterns 6 made of AI-Cu, etc., are connected to the both ends of said pattern 5. When a pulse current IG is conducted in the exothermic resistance pattern 5, a downward partial magnetic field is impressed on part of the corresponding magnetic thin film 4. The direction of magnetizing the magnetic thin film 4 is inverted to point downward Y, and the magnetic bubble 8 is generated. The current value IG required for generating the magnetic bubble is minimized by raising the temperature of the magnetic thin film 4 after the conductive pattern heats. Consequently power consumption can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bubble generating group for a magnetic bubble memory. Magnetic bubble memory can be applied to various electronic devices as a memory that can record information at high density.

[Prior art and its problems] At present, as external memory for computers, memory for electronic files, memory for still image files, etc., there are magnetic tapes, Winchester disks, floppy disks, optical disks, magneto-optical disks, etc. Various types of memory devices are used. These memory devices require a recording/reproducing head to be moved relative to the memory when recording or reproducing information. That is, with such relative movement of the head, the head records an information string fixedly on the information track or reproduces the information string fixedly recorded on the information track.

However, in recent years, as there has been a demand for increasingly higher recording densities, tracking control to make the head accurately follow the information track has become more complex, and the quality of recorded and reproduced signals may deteriorate due to insufficient control. The quality of recorded and reproduced signals deteriorates due to vibrations in the head moving mechanism and dust adhering to the surface of the memory.Furthermore, in the case of a memory that performs recording and reproduction while in contact with the head, such as a magnetic tape, sliding causes a! In the case of a memory that performs recording and reproduction without contact with the head, such as an optical disk, focusing control is required, and if this control is insufficient, the quality of the recording and reproduction signal may deteriorate. There is a problem of doing so.

On the other hand, magnetic bubble memory can record information at a predetermined position and transfer the recorded information, and can reproduce information at a predetermined position while transferring the information. There is no need for relative movement with Qc11. It is believed that the above-mentioned problems will not occur even when the technology becomes more sophisticated, and high reliability can be achieved.

Incidentally, in a magnetic bubble memory, a bubble generator is provided to appropriately generate magnetic bubbles in a magnetic thin film.

FIG. 4 shows an example of a bubble generator in a conventional magnetic bubble memory. FIG. 4(a) is a partial Y-plane view;
Figure (b) is the BB sectional view.

In the figure, 2 is a substrate made of non-magnetic garnet such as GGG, NdGG, etc., and a magnetic garnet thin film 4 is provided on the substrate. The film can be formed by, for example, a liquid phase epitaxial growth method (LPE method), and its thickness is, for example, about 5 pm. An upward bias magnetic field HB is applied from the outside, and the magnetic thin film 4
is magnetized upward as shown by arrow X.

A conductor pattern 6 having a hairpin-shaped portion is provided on the magnetic thin film 4. The conductor pattern is made of, for example, Al-
It is made of Cu, Au/Mo, etc. When the magnitude of the bias magnetic field HB is set to a positive value and a pulse of a positive magnitude is applied to the conductor pattern 6 in the direction of the arrow, the magnetic thin film 4 corresponding to the hairpin-shaped portion of the conductor pattern 6 is applied. A downward local magnetic field is applied to the portion, and the magnetic field reverses the direction of magnetization of the magnetic g film 4 so that it becomes downward as shown by arrow Y, thus generating a magnetic bubble 8.

However, the conventional magnetic bubble generators described above require considerably large power consumption in order to generate magnetic bubbles.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve one or more problems in conventional bubble generators for magnetic bubble memories, and to provide a bubble generator with low power consumption.

[Means for Solving the Problems] According to the present invention, in order to achieve the above-mentioned objects, in a bubble generator of a magnetic bubble memory that records information using magnetic bubbles in a magnetic thin film, a magnetic bubble generator is provided. A magnetic bubble characterized in that an energizing pattern is formed on the thin film to generate a local magnetic field for generating magnetic bubbles that is substantially perpendicular to the surface of the magnetic thin film, and the energizing pattern is made of a heating resistor. A memory bubble generator is provided.

[Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1(a) is a partial plan view of the bubble generator of the magnetic bubble memory according to the present invention, and FIG. 1(b) is a partial plan view of the bubble generator of the magnetic bubble memory according to the present invention.
FIG.

In FIG. 1, 2 is a non-magnetic garnet substrate, and 4 is a non-magnetic garnet substrate.
is magnetic garnet %ilN. An upward bias magnetic field HB is applied from the outside, and the magnetic thin 115!4
is magnetized upward as shown by arrow X.

A hairpin-shaped heating resistor pattern 5 is provided on the magnetic thin film 4 as an energization pattern for generating a local magnetic field for generating magnetic bubbles.

For example, HfB2 is used as the heating resistor, and its thickness is, for example, about 0.17 zm, and its specific resistance value is, for example, about 270 ΩφCm (by the way, A
I is 2.5 Ω*cm).

Wiring conductor patterns 6 for voltage application are connected to both ends of the heating resistor pattern 5. The conductor pattern is A1-Cu, Au/Mo, which was explained with reference to FIG. 4 above.
A conductor such as the above is used, and its thickness is, for example, about lpm.

In this embodiment as well, similarly to the conventional magnetic bubble generator, the magnitude of the bias magnetic field HB is set to an appropriate value,
Furthermore, a pulsed electric current 11 of an appropriate size is applied to the heating resistor pattern 5 through the conductor pattern 6 in the direction of the arrow. When IG is applied, a downward local magnetic field is applied to the part of the magnetic hook 4 corresponding to the heating resistor pattern, and the magnetic thin film 4 is
The direction of magnetization is reversed and becomes downward as shown by arrow Y, thus generating a magnetic bubble 8.

By the way, the current value necessary for generating a magnetic bubble by applying the pulse current IG is (Hk-4πM s
) is proportional to Here, Hk is the anisotropic magnetic field and Ms is the saturation magnetization of the magnetic thin film 4.

Figure 2 shows (YSmLuCa)3(Fe) as a magnetic fJ film.
As can be seen from Figure 0, which shows the temperature change graph of Hk and 4πMs when using Ge) 501z, both Hk and 4πMs decrease as the temperature increases, but the rate of decrease in Hk is at a rate of decrease of 4τMs. It is extremely large compared to (
Hk-4πM s ) decreases rapidly as the temperature rises.

Figure 3 shows the current value IG required to generate the above magnetic bubble.
3 shows a graph of the temperature change of the heat generating resistor pattern 5, and also shows the relationship between the resistance value R1 of the heat generating resistor pattern 5, the current value 1 flowing through the pattern, and the heat generating temperature T. Since R1 is large, the current value 11 at the intersection of the graph of the current value IG necessary for magnetic bubble generation and the graph of the current value 11 is relatively small.

FIG. 3 shows the resistance value R2 and the current value flowing through the conductor pattern 6 when the conductor pattern 6 (resistance value R2) as shown in FIG. 4 is used instead of the heating resistor pattern 5 of this embodiment. It also shows the relationship between I2 and the heat generation temperature T. In this case, since the resistance value R2 of the conductor pattern 6 is extremely small, the current value at the intersection of the graph of the current value IG necessary for magnetic bubble generation and the graph of the current value I2 12 is relatively large.

As described above, magnetic bubbles can be generated with a small current by using the heat generating resistor pattern 5 as a conduction pattern for generating a local magnetic field for generating magnetic bubbles that is substantially perpendicular to the film surface of the magnetic thin film 4.

[Effects of the Invention] According to the present invention as described above, when a current is applied to generate a local magnetic field for generating magnetic bubbles, the energization pattern generates heat and the temperature of the magnetic thin film increases, so that magnetic bubbles are generated. The current 4 for this purpose can be small, and therefore power consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1(a) is a partial plan view of the magnetic bubble generator of the present invention, and FIG. 1(b) is a sectional view taken along line BB. 2 and 3 are graphs showing the characteristics of the magnetic bubble generator. FIG. 4(a) is a partial plan view of the magnetic bubble generator,
FIG. 4(b) is a sectional view taken along line B-B. 2: Substrate, 4: Magnetic thin film, 5: Heat generating resistor pattern, 6: Conductor pattern, 8: Magnetic bubble. Agent Patent Attorney Jo Yamashita Figure 1 (Q) @1 Figure (b) Figure 2 (7 Figure C6゜Figure 3 Figure 4 (Q) Figure 4 (b)

Claims (2)

[Claims] (1) In a bubble generator for a magnetic bubble memory that records information using magnetic bubbles in a magnetic thin film, to generate a local magnetic field for generating magnetic bubbles on the magnetic thin film that is almost perpendicular to the surface of the magnetic thin film. 1. A bubble generator for a magnetic bubble memory, characterized in that an energizing pattern is formed, and the energizing pattern is made of a heating resistor. (2) A bubble generator for a magnetic bubble memory according to claim 1, wherein the energization pattern has a hairpin shape.