JPS5918788B2 - Magnetic bubble generation method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a magnetic bubble generation method.

In general, a magnetic bubble device has a mechanism that controls the generation and erasure of magnetic bubbles, a mechanism that transfers the magnetic bubbles, a memory loop that stores the magnetic bubbles, and finally a mechanism that detects the presence of magnetic bubbles and converts them into electrical signals. It is equipped with a detection mechanism for taking out the device.

The present invention particularly relates to a mechanism for generating the above-mentioned magnetic bubbles. In general, bubble generators that generate magnetic bubbles in magnetic bubble memory chips for magnetic bubbles such as orthoferrite and magnetic garnet can be roughly divided into disk type and hairpin conductor type. A conductor is created on a magnetic thin plate by photo-etching or the like.A magnetic bubble is formed by passing a pulse current with a relatively large amplitude through this hairpin conductor to create a strong magnetic field.

In this case, the magnetic field obtained by the current flowing through the hairpin conductor is the nucleation magnetic field HN (Nucreation magnetic field HN).
Fie1d) must be exceeded. The magnitude of the nucleation magnetic field HN is approximately equal to the anisotropic magnetic field HK, and this value has a magnitude of approximately 20,000e. The anisotropic magnetic field HK increases as the bubble diameter becomes smaller; They tend to become smaller as the temperature rises.On the other hand, it is known that in order to increase the bit density of the memory loop that stores magnetic bubbles, the diameter of the magnetic bubbles must be reduced; As HN decreases, the nucleation magnetic field HN increases accordingly, and the amplitude of the pulse current supplied to the hairpin conductor must be set large.

However, if the amplitude of the pulse current is increased in this way, the permissible current value of the hairpin conductor may be exceeded and the hairpin conductor may be burnt out. Also, it becomes difficult to generate bubbles, and a current with a large amplitude is generated. Since it requires a circuit, it is also economically disadvantageous.
Therefore, an object of the present invention is to ensure the reliability of bubble generators such as hairpin conductors by reducing the amplitude of the pulse current required to generate magnetic bubbles, and to simplify the circuit that generates the pulses. This ensures economic efficiency and also ensures the generation of bubbles. In order to achieve such an object, the present invention supplies a bubble generator such as a hairpin conductor with a pulse current having a polarity opposite to that of the bubble generation pulse current. will be described in detail below using examples.

Generally, it is known that the anisotropic magnetic field HK decreases as the temperature of the magnetic bubble memory chip increases. Therefore, in this case, the anisotropic magnetic field HK
By reducing the amplitude of the pulse current, the amplitude of the pulse current can naturally be reduced. Based on this principle, the drawing shows a current waveform for preheating the periphery of a magnetic bubble memory chip where a hairpin conductor is formed immediately before generating a bubble. In the figure, P is a pulse current of amplitude A1 for generating magnetic bubbles. Further, P2 is a pulse current having a polarity opposite to that of the pulse current P1 formed before time T. In this case, the current P2 is set to have an amplitude and a pulse width sufficient to reduce the anisotropic magnetic field HK by heating the periphery of the bubble chip in which the hair conductor is formed with the Joule heat generated by energization. Therefore, by supplying this pulse current P2, the peripheral part of the hairpin conductor can be heated in advance before the bubble domain is generated.
Since the anisotropic magnetic field HK can be made small, the amplitude A1 of the pulse current P for generating magnetic bubbles can be made small. here,
A plurality of pulse currents P2 may be formed before the generation of the magnetic bubble, which is limited to the formation of one pulse current P2.

In this way, since the preheating pulse current P2 has a polarity opposite to that of the magnetic bubble generation pulse current P, magnetic bubbles are not generated even if the amplitude is large.

Therefore, since the amplitude of the pulse current P2 can be set arbitrarily, the configuration of the circuit that generates the pulse can be simplified and economical efficiency can be ensured. As explained above, according to the magnetic bubble generation method of the present invention, when a pulse current is passed through a bubble generator such as a hairpin conductor wire formed in a magnetic bubble memory chip to generate a magnetic bubble, the polarity of the pulse current is reversed in advance. The surrounding area of the bubble generator was heated by passing a pulsed current of , and its anisotropic magnetic field HK was reduced.

For this reason, the amplitude of the pulse current for generating magnetic bubbles can be reduced, which prevents burnout of the magnetic bubble generator.
In addition, small-diameter magnetic bubbles such as submicron bubbles can be reliably formed even at low temperatures, and the amplitude of the preheating pulse current can be set arbitrarily, so the configuration of the circuit that generates the pulses can be simplified, and various other effects can be achieved. .

[Brief explanation of the drawing]

Claims (1)

[Claims] 1. Before supplying the pulse current for magnetic bubble generation to the bubble generator formed in the magnetic bubble memory chip, a pulse current of opposite polarity to this pulse current is supplied to preheat the magnetic bubble generation part. A magnetic bubble generation method featuring