JPS5931150B2 - magnetic bubble module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble module, and particularly to a magnetic bubble module whose operating margin is not narrowed due to temperature changes.

A magnetic bubble module consists of a magnetic bubble chip made of a magnetic thin film, lead wires for connection to an external circuit, a drive coil that applies a horizontal rotating magnetic field to the chip to transfer magnetic bubbles, and a drive coil that transfers magnetic bubbles by applying a horizontal rotating magnetic field to the chip. The main structure is a magnet block that applies a bias magnetic field in the perpendicular direction to effectively create magnetic bubbles. FIG. 1 is a simplified configuration diagram showing the plane of the conventional magnetic bubble module of the above type. In the figure, 1 is a plurality of magnetic bubble chips arranged on a substrate 2, each connected to a lead wire 3. be done.

A second layer is placed around one or more layers of this plane.
As shown in the figure, driving coils 4 and 5 are wound in the X direction and Y direction, which are arranged perpendicularly to each other, and a permanent magnet 6 and a yoke plate 7 that provide a bias magnetic field are arranged. Both drive coils 4 and 5 are supplied with currents having different phases, and supply a rotating magnetic field in the horizontal direction to the bubble chip 1.
Actually, a sine wave current is supplied to the X-direction drive coil 4, and a cosine wave current is supplied to the Y-direction drive coil 5. The permanent magnet 6 supplies a perpendicular bias magnetic field to the magnetic bubble chip 1, and the magnetic circuit of the permanent magnet 6 is formed by a yoke plate 7 made of a high permeability magnetic material such as permalloy or ferrite. In such a configuration, X
When current is applied to the coils 4 and 5 for driving in the direction and Y direction,
These coils 4 and 5 generate heat, and therefore the temperature of the bubble lip 1 changes by operating or stopping the module. On the other hand, many of the characteristics of the bubble chip 1 are highly temperature dependent; for example, the anisotropic magnetic field, optimum bias magnetic field, and bubble diameter have large temperature coefficients.

Therefore, large temperature changes cause the operating margin to become narrow. Therefore, an object of the present invention is to prevent the operating margin from narrowing even if the temperature of the bubble chip changes.

In order to achieve such an object, the present invention automatically controls a control circuit or a bias magnetic circuit based on temperature changes of a bubble chip, and will be described in detail below using examples.

Various methods can be considered to accurately measure the temperature of the magnetic bubble chip 1, but the resistance value of a metal thin film pattern for magnetic bubble detection or magnetic bubble control formed on the bubble chip 1 is measured, and then the temperature of the bubble chip is measured. The best method is to detect the temperature of FIG. 3 is a plan view showing the entire bubble chip 1, in which 31 is a bubble generator, 32 is a transfer path, 33 is a replicator that divides and duplicates the bubbles in the transfer path 32, and 34 is a bubble detector. This is a soft ferromagnetic magnetoresistive element such as permalloy, and as shown in FIG. The replication bubble passes through the element 41 to this detector 3.
4, it is enlarged as it approaches 4, and when it reaches this detector 34, it is detected as an electrical signal.

In addition, in FIG. 3, 35 is a bonding pad. Therefore, in such a configuration, bubbles are generated by the nucleation magnetic field HN formed by the bubble generator 31, transferred on the transfer path 32, and replicated by the replicator 33,
It is detected by the detector 34. In this embodiment, the temperature of the chip itself is detected by measuring the resistance value of the bubble detector 34.

That is, the detector 34 is made by cutting a permalloy thin film into a fine pattern, and its resistance value is about 1KΩ. As a result of measuring the temperature dependence of the resistance value of this detector 34, the temperature coefficient α is 0.32%/0C, which is 10
It remained unchanged in the range of 50°C to 50°C. The temperature coefficient changes depending on the Nl-Fe composition ratio of the permalloy thin film,
It can be easily determined by measuring between pads using a constant temperature bath. In this example, a method is shown in which a metal thin film pattern for detecting magnetic bubbles formed on a chip 1 is directly used as a thermometer.
is the best way to detect temperature. In this embodiment, the metal thin film pattern for detecting magnetic bubbles is used as a temperature measuring resistor, but the present invention is not limited to this. Of course, such a metal thin film pattern for magnetic bubble control can be used as a temperature measuring resistor. Next, in this embodiment, as described above, the bubble detector 34 of the bubble chip 1
The temperature is detected by measuring the resistance value of the magnet, and the bias magnetic circuit is controlled based on this.A specific circuit is shown in FIG.

In the figure, 1a is a detector that measures the resistance value of a bubble detector 34 formed in the bubble chip and sends out an output corresponding to the temperature of the bubble chip 1, and 2a is a detector that measures the change in the output output from the detector 1a. 3a is a control circuit, 4a is a DC power supply, 5a is an input, and 6a is an electromagnet for forming a bias magnetic field. In such a configuration, by detecting the change ΔV in the output value of the detector 1a by the detection circuit 2a and inputting this ΔV to the control circuit 3a,
A corresponding current flows through the electromagnet 6a to change the magnetic field strength of the bias magnetic circuit. The current value of the bubble control circuit can be changed in a similar manner. In the conventional module, the operating margin of the bubble 1 was several Oersteds, but in the module according to the present invention, it is 10 Oersteds, which significantly increases the operating range.

Further, according to the present invention, there is an advantage that the module operates normally even when the ambient temperature of the module changes. As explained above, in the present invention, the bubble control circuit operates according to the amount of change in the resistance value of the metal thin film pattern for detecting magnetic bubbles formed directly on a bubble chip or for controlling magnetic bubbles such as a magnetic bubble replicator. The current value or the magnetic field strength of the bias magnetic circuit is controlled.

Since the metal thin film pattern used for temperature detection is formed directly on the bubble chip, its resistance changes reliably and quickly follow the temperature changes of the chip, so the above-mentioned control can be performed accurately and quickly. Instead, the temperature-measuring resistor is also used as a metal thin film pattern for detecting or controlling magnetic bubbles, so extra space and wiring for the temperature-measuring resistor are unnecessary, and high-density magnetic bubbles can be used. advantageous to Furthermore, since there is no need to separately form a temperature measuring resistor on the chip, it is advantageous in terms of cost.

[Brief explanation of the drawing]

1 and 2 are perspective views showing an example of a magnetic bubble module, FIGS. 3 and 4 are plan views showing details of a magnetic bubble chip, and FIG. 5 is an embodiment of a magnetic bubble module according to the present invention. FIG. 2 is a circuit diagram for explaining an example. 1...magnetic bubble chip, 2...substrate, 3...lead wire, 4, 5...X-direction, Y-direction driving coil, 6... ...Permanent magnet, 7.
... Yoke plate, 1a ... Detector, 2a.
...detection circuit, 3a ...control circuit, 4a
...DC power supply, 5a...Input, 6a.
...Electromagnet, 33...Replicator, 34...
...Bubble detector.

Claims (1)

[Claims] 1. In a magnetic bubble module equipped with a bubble chip placed in a rotating magnetic field and a bias magnetic field, according to the amount of change in the resistance value of a metal thin film pattern for magnetic bubble detection or magnetic bubble control formed on the bubble chip. A magnetic bubble module characterized in that the current value of a bubble control circuit or the magnetic field strength of a bias magnetic circuit is changed.