JPS647437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic bubble detector in a magnetic bubble memory device.

In a magnetic bubble memory device, a soft magnetic thin film transfer path, or a soft magnetic thin film transfer path and an ion implantation transfer path are formed on a bubble crystal, and a bubble is generated according to information using a bubble magnetic domain generator. The information is transferred to the bubble transfer path and stored. The stored information is read by transferring the bubbles to a magnetic bubble detector that utilizes the magnetoresistive effect.

Conventionally, this magnetic bubble detector uses a so-called thick film type detector that is manufactured at the same time as a soft magnetic thin film transfer path. Since the output of this thick-film detector largely depends on the strength of the rotating magnetic field that drives the bubble, it is difficult to obtain good overall device characteristics unless the driving magnetic field that gives the output peak matches the central driving magnetic field of the element. Can not.

[Conventional technology]

FIG. 5 is a diagram showing a conventional magnetic bubble detector. This is the pattern width of 1 μm and pattern period used in a 1M bit device that uses a 1.9 μm bubble and 8 μm period half disk pattern for the transfer path.
It is a 10.4μm asymmetric chevron type detector.
In the figure, 1 is a bubble expander, 2 is a detector,
The arrow indicates the direction of bubble travel. As shown in FIG. 6, the characteristics of this magnetic bubble detector are such that the output peak (indicated by arrow A) and the central driving magnetic field of the element (indicated by arrow B) match well.

[Problem that the invention seeks to solve]

In the magnetic bubble detector described above, if a 4M-bit element with a 1.3 μm bubble and a 4 μm period wide gap pattern is used as the transfer path, the center driving magnetic field of the element will move to the higher side, and the output peak of the detector will rise. The drawback was that the output value deteriorated due to a large deviation from the driving magnetic field that gave the output.

[Means for solving problems]

The present invention provides a magnetic bubble detector that solves the above problems, and the present invention provides a magnetic bubble detector formed with an asymmetric chevron pattern using a soft magnetic thin film, which contributes to the transfer of bubbles. The connection between the elemental piece and the bubble expander at the front stage of the detector is intricate and has an apparent gap of zero, and the connection between the elemental piece that contributes to the bubble detection output and the bubble expander at the rear stage is a gap of about 1 μm. This is done using magnetic bubble detectors, which are characterized in that they are arranged so that they are in contact with each other while maintaining the same.

[Effect]

The above-mentioned magnetic bubble detector has an apparent gap of zero in the connection between the elemental piece that contributes to bubble transfer and the bubble expander at the preceding stage, and the elemental piece that contributes to the bubble detection output and the subsequent stage. By providing a gap of approximately 1 μm between the connection with the bubble expander, the driving magnetic field that gives the output peak of the detector matches the central driving magnetic field of the element.
Deterioration of the output value can be prevented.

〔Example〕

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

FIG. 1 shows a main part of an embodiment of the present invention as a plan view, and FIG. 2 shows a partially enlarged view thereof. In the figure, 10 is a bubble detector, 11 is a part that contributes to bubble transfer, 12 is a part that contributes to bubble detection output, 13 is a bubble expander in the front stage of the detector,
Reference numeral 14 indicates a bubble expander located after the detector.

In this embodiment, as shown in FIGS. 1 and 2, the pattern period b of the portion 11 that contributes to bubble transfer is long, the pattern period a of the portion 12 that contributes to output is shortened, and the portion 11 that contributes to transfer is made short. The pattern width c is made thicker than the pattern width d of the portion 12 that contributes to the output, so that the overall shape is asymmetric chevron type,
The connection between the elemental piece of part 11 that contributes to bubble transfer and the bubble expander 13 in the previous stage is made in a convoluted manner to avoid any apparent gap, and the elemental piece of part 12 that contributes to the output and the bubble expander 13 in the latter stage are connected in a convoluted manner. The connection with the vessel 14 should be made so that the straight lines face each other,
A gap G of about 1 μm is provided between them.

The characteristics of this embodiment formed in this manner are shown in FIG. The figure shows the bias magnetic field on the vertical axis and the triangular wave drive magnetic field on the horizontal axis, and the bubble detection output is 3.5 mv ~ 8
The output characteristics of mv are shown by curves a to g. Note that the arrow h indicates the central magnetic field for element transfer, and the arrow i indicates the driving magnetic field that provides the peak of the bubble detection output. The figure shows that the output peak could be shifted to the high drive side (70Oe in this case) without deteriorating the transfer characteristics.

FIG. 4 is a diagram showing the pattern width and cycle dependence of the driving magnetic field that gives the output peak of the detector. Curve A in the figure is the relationship between the detector pattern width and the driving magnetic field.
Curve B shows the relationship between the detector pattern period and the driving magnetic field. As shown in the figure, the driving magnetic field that gives the output peak of the detector shifts to the higher driving magnetic field side as the pattern width of the detector becomes thicker, and shifts to the lower driving magnetic field side as the pattern period becomes longer. The pattern width of the conventional detector shown in Figure 5 is 1.1 μm, and the pattern period is
The driving magnetic field that gives the output peak at 10.4 μm corresponds to the central driving magnetic field of the element, 57 Oe. Therefore, if this detector is used as it is in a high-density element with a central driving magnetic field of 70 Oe, it will not be possible to obtain sufficient output, especially in a high driving magnetic field, unlike the driving magnetic field that gives an output peak. On the other hand, bubble detection involves stretching the bubbles into stripes, and requires sufficient driving force to transfer the striped bubbles in addition to output characteristics. Generally, when the pattern period is lengthened, the ability to stretch and transfer bubbles increases, but conversely, as shown in FIG. 4, the output characteristic shifts to the low drive side, and the high drive side deteriorates. Therefore, this embodiment has the configuration described above in FIGS. 1 and 2.

〔Effect of the invention〕

As explained above, according to the present invention, by making the detector shape as shown in FIGS. 1 and 2, the driving magnetic field that gives the output peak of the detector and the central driving magnetic field of the element can be separated. This makes it possible to prevent deterioration of the output value.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams for explaining one embodiment of the magnetic bubble detector of the present invention, Figure 3 is a diagram showing the characteristics of the magnetic bubble detector of the present invention, and Figure 4 is a diagram for explaining the characteristics of the magnetic bubble detector of the present invention. FIG. 5 is a diagram showing the pattern width and cycle dependence of a driving magnetic field that gives an output peak, FIG. 5 is a diagram showing a conventional magnetic bubble detector, and FIG. 6 is a diagram showing its characteristics. In the figure, 10 is a bubble detector, 11 is a part that contributes to bubble transfer, 12 is a part that contributes to bubble detection output, 13 is a bubble expander in the front stage of the detector,
Reference numeral 14 indicates a bubble expander located after the detector.

Claims (1)

[Claims] 1. In a magnetic bubble detector formed with an asymmetric chevron pattern using a soft magnetic thin film, the connection between the elemental piece that contributes to bubble transfer and the bubble expander in the front stage of the detector is complicated. The mold has an apparent gap of zero, and the connection between the elemental piece that contributes to the bubble detection output and the bubble expander in the subsequent stage is characterized by being arranged so that they are in contact with each other with a gap of approximately 1 μm. Magnetic bubble detector. 2. In the magnetic bubble detector according to claim 1, the relationship between the pattern widths of the elemental pieces that contribute to bubble transfer and the elemental pieces that contribute to output is about 3:1, and the elemental pieces that contribute to transfer A magnetic bubble detector characterized in that the pattern period of the magnetic bubble detector is 1.3 to 1.6 times the pattern period of the elemental piece contributing to the output.