JPH03266286A - Magnetic bubble device provided with ion implantation transfer line - Google Patents

Abstract

PURPOSE:To make the bubble extinguishment of a bubble detector sure by specifying the relation between the patter width of the leader line of the joint of a hair pin type conductor pattern and the conductor pattern width of a hair pin part. CONSTITUTION:The form of the joint of a first hair pin type conductor pattern 20 to flow a pulse current for enlarging bubble is devised and a pattern width W of the leader part of joints 21 and 22 of the hair pin type conductor pattern 20 and an open angle theta of the both joints are made into precise values. That is, the pattern width W is made more than one and a half times as wide as a conductor pattern width (w) of a hair pin gap forming part or the open angle is made more than 120 degrees. Accordingly, an elongated and enlarged bubble is not overflown to the external part of the effective area of the conductor pattern 20 to flow a bubble extinguishing pulse current. Thus, the bubble is extinguished surely and an erroneous action is prevented.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a magnetic bubble memory device equipped with a bubble transfer path using an ion implantation method, and is particularly suitable for preventing malfunctions due to the generation of unnecessary bubbles in a current stretch type magnetic bubble detector. The present invention relates to a magnetic bubble device having an improved magnetic bubble detector. [Prior Art] In order to achieve high integration as a magnetic bubble memory element, instead of the conventional permalloy thin film pattern in the magnetic bubble transfer path,
Devices using ion implantation transfer paths are promising. Hereinafter, magnetic bubbles will be simply referred to as bubbles, but in the ion implantation transfer path, for example, H2"
It is formed by partially implanting ions such as , He'', Ne+, etc. By magnetizing this ion implanted layer with a magnetic field that rotates in the plane, moving magnetism is generated at the boundary of the ion implanted area. This magnetic pole is used to transfer bubbles.As related to this type of transfer path, for example,
I.E.E. Transaction Action on
Magnetics, MG-13,6 (1977)
Pages 1744-1764 (I E3Trans,
Magn, MAG-13, No. 6 (1977) P
, 1744-1764). When constructing a magnetic bubble memory element using such an ion implantation transfer path, in order to input and output information,
Elements such as bubble detectors are used that convert magnetic bubbles into electrical signals. Hereinafter, an outline of a conventional bubble detector will be explained according to the drawings. Figure 5 shows a plan view of the main parts of a conventional bubble detector.Bubbles are stretched and expanded in a string-like manner along the gap of a conductor pattern using a pulsed current, and the leakage magnetic field from the string-like bubbles is generated. This detector uses the magnetoresistive effect to convert bubbles into electrical signals and detect them, and is commonly known as the "current stretch method." In the figure, reference numeral 10 denotes an ion implantation transfer path for transferring magnetic bubbles, the periphery of which is surrounded by an ion implantation region 2, and the inner region consisting of a non-ion implantation region STR. 2
0 is the first nonmagnetic conductor pattern for passing a pulsed current that stretches and expands the bubble like a string, and has a hairpin pattern as shown in the figure, and is made by laminating nonmagnetic good conductor thin film patterns such as Au. It is formed by By magnetizing the transfer path 10 with the rotating magnetic field HR, the bubble moves on the transfer path 10 and is transferred, but when the bubble transferred in the direction of arrow P reaches the gap g of the hairpin conductor 20, A stretching pulse current is applied from an external circuit to stretch and expand the bubble. 30 is. A magnetic resistance pattern (a) that converts the presence or absence of bubbles into an electrical signal
(resistance effect element), usually made of permalloy etc.
It consists of ~800 thin film patterns. 4 indicated by dashed line
0 is a second non-magnetic conductor pattern, which is a conductor pattern that passes a pulse current to extinguish bubbles after being detected, and the first conductor pattern 20 is
They are laminated with an insulating layer interposed therebetween. This second conductor pattern 40 can also be used in common with the conductor pattern 20 that expands the bubble, and in this case, the pattern 40 can be omitted. [Problems to be Solved by the Invention] The conventional bubble detector described above has the following problem of malfunction. That is, after the bubble has been enlarged and detected, the bubble becomes unnecessary and disappears by passing a pulse current for extinction through the conductor pattern 40. However, this extinguishing operation cannot be reliably realized, and the bubbles whose extinguishing operation has failed remain as unnecessary bubbles 100 around the conductor pattern 40. Extra unnecessary bubble 1 due to malfunction caused in this way
02 causes a problem in that as the memory operation is repeated many times, it jumps into the bubble transfer path and destroys the read information. Therefore, an object of the present invention is to solve the problem of such conventional malfunctions, and to provide an improved bubble detector that can reliably realize bubble extinguishing operation and prevent unnecessary residual bubbles from remaining. An object of the present invention is to provide a magnetic bubble device. [Means for Solving the Problems] In order to achieve the above object, the present inventors have developed a magnetoresistive pattern 30 or an ion implantation transfer path pattern 10 constituting a detector, as well as a conductor pattern 20.40.
We examined the shapes of the following in detail. As a result, the following findings were obtained. The present invention was made based on these findings, and will be sequentially explained below. First, FIG. 6 is a plan view of the main part of the detector, illustrating the results of an investigation into the malfunction mechanism that causes the bubble extinguishing operation to fail in the conventional bubble detector shown in FIG. 5. In addition, in FIGS. 6(a) and 6(b), the magnetoresistive element pattern 30 and the second hairpin-type conductor pattern 40 are omitted, respectively, since the drawings would be complicated. In addition, in FIGS. 6(C) and (d), the magnetoresistive element pattern 30 and the first hairpin conductor pattern 2
0 has been omitted. FIGS. 6(a) and 6(b) both show the shape of a bubble that is elongated and enlarged by passing a pulse current for bubble elongation through the first hairpin conductor pattern 20. FIG. 4A shows an example of a bubble 100 operating normally, and FIG. 1B shows an example of a bubble 101 operating abnormally. In the case of the same figure (a) where the bubble is correctly extended and enlarged,
The bubble 100 is expanded into a string shape along the longitudinal direction of the gap g of the hairpin conductor pattern 20. As a result, the string-like bubble 100 is removed by the second hairpin-shaped conductor pattern 4 through which a pulse current is passed to extinguish the string-like bubble 100.
It exists in the gear g of 0. Note that the second hairpin conductor pattern 40 is omitted here (see FIG. 5).
It can also be used as the conductor pattern 20, in which case the conductor pattern 40 is unnecessary). On the other hand, in the case of the bubble 101 shown in FIG. 6B, in which the bubble is not enlarged correctly and operates abnormally, the bubble 101 largely protrudes outside the gap of the hairpin-shaped conductor pattern 20, and the string-shaped bubble 101 has a protruding portion E. become. On the other hand, FIGS. 6(C) and (d) are respectively shown in FIG.
This figure shows the state in which the bubbles elongated and expanded in a) and (b) are extinguished by passing a bubble extinguishing pulse current through the second hairpin conductor pattern 40. In the case of FIG. 4C, the bubble 100 enlarged in FIG.
Since it is inside the , it can be definitely destroyed. On the other hand, in the case of FIG. 4D, the bubble 101 enlarged in FIG. Therefore, even if the annihilation pulse current is applied, this protruding portion E is not annihilated, and as shown in the figure, E
It has been found that some bubbles remain as unnecessary bubbles 102, resulting in malfunction. The present inventors have discovered the reason why, in the malfunction mechanism described in FIG. As a result of investigation, it was found that this occurs due to the following two causes. This will be explained below using FIGS. 7 and 8. The first cause is the current magnetic field H1 generated when a pulse current that expands the bubble is passed through the hairpin conductor pattern 20. In FIG. 7(a), this magnetic field H1 generated inside the hairpin-type conductor pattern 20 (inside the gear g) is in the direction of expanding the bubble, but the widened portions 21 and 22 of the base of the pattern 20 (both A magnetic field H1 is also generated in this direction outside the gear (g). Due to this magnetic field H1, as shown in FIG. 7(b), the bubble becomes a string-shaped bubble 1011 which extends along the root portion 21 and largely protrudes to the outside. This is the part where the working part protrudes excessively [corresponding to E in Fig. 6(b)]. The second reason why the enlarged bubble protrudes is the magnetic field Hp generated by the magnetoresistive pattern 30. In FIG. 8(a), the magnetoresistive pattern 30 is, as described above,
It is formed of a soft ferromagnetic thin film such as Malloy with a film thickness of about 400 to 800. This pattern is magnetized by an in-plane rotating magnetic field HR applied from the outside to transfer bubbles, and generates a magnetic field HP. In the figure (a), when the rotating magnetic field HR points in the A direction, a magnetic field HP is generated in the direction of expanding the bubble at the 30A section, and along this magnetic field, the bubble is pulled as shown in the figure (b). String-shaped bubble 1 that has been stretched and protrudes outward
01 It becomes like PA. This PA section is an extra thick part [corresponding to E in FIG. 6(b)]. Furthermore,
When the rotating magnetic field HR turned in the B direction, a magnetic field UP was generated in the 30B section that expanded the bubble, and along this magnetic field, the bubble was stretched as shown in the same figure (C) and protruded greatly to the outside. It becomes like string-shaped bubble 101 PB. P
Part B is the part that protrudes excessively. Therefore, the inventors of the present invention have proposed that if the bubble expanded at the time of detection does not protrude outside the effective area ANH of the conductor pattern through which the bubble extinguishing pulse current flows, the bubble after detection can be prevented from leaving unnecessary bubbles. We have obtained the knowledge that it is possible to reliably eliminate the problem and prevent malfunctions. The present invention has been made based on this knowledge, and specific means for achieving the objective are shown below. The above-mentioned objects of the present invention are as follows: (1) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, drawing out the root of a hairpin-shaped conductor pattern through which a pulsed current is passed to expand a magnetic bubble. When the line pattern width is W and the conductor pattern width of the hairpin portion is ω, W is at least 1.5 times −, preferably 4≧W/−≧1.
(2) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, a hairpin-shaped conductor pattern is placed on which a pulsed current is applied to expand the magnetic bubble. The opening angle θ of the root pulling line is at least 120°, preferably 120'≦θ≦1 for practical purposes.
(3) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, the pattern of the drawing line part of the magnetoresistive pattern can be , U-shaped or L-shaped, preferably at least one of these.
Also by a magnetic bubble device formed by ensuring that the seeds are present in the non-ion implantation region STR. (4) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, an auxiliary pattern made of the same material as the magnetoresistive pattern is arranged in the lead line portion of the magnetoresistive pattern. (5) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, the lead wire of the magnetoresistive pattern is connected to the magnetoresistive pattern. This is achieved by a magnetic bubble device that extends linearly on an extension of the pattern. [Function] As described above, the bubble detector of the present invention can be extended and expanded by improving the shape of the magnetoresistive pattern, the ion implantation transfer path pattern, or the conductor pattern forming the detector. The bubble is prevented from protruding outside the effective area of the conductor pattern through which the bubble extinguishing pulse current flows. As a result, bubbles can be reliably extinguished and malfunctions can be prevented. [Example 1] Hereinafter, an example of the present invention will be described with reference to the drawings. Example 1 FIG. 1 shows an example of a bubble detector according to the present invention, in which the shape of the hairpin conductor pattern is improved to prevent the malfunction described in FIG. 7. It is. In other words, by the pulsed current magnetic field for bubble expansion,
This figure shows an example of preventing a malfunction in which a bubble protrudes outward along the base of a hairpin-shaped conductor 20. Note that, since the drawing is complicated, this drawing does not show the magnetoresistive effect pattern 30 or the bubble extinguishing conductor pattern 4 after detection.
0 was omitted. In Figure 1, the first
The shape of the base of the hairpin-type conductor pattern 20 is
It is characterized by its ingenuity, and in that the pattern width W of the drawn-out portions of the bases 21 and 22 of the hairpin-shaped conductor pattern 20 and the opening angle θ of both of these are set to appropriate values. That is, by making the pattern width W 1.5 times or more the conductor pattern width - of the hairpin gap forming part (W/-≧1.5), or by making the opening angle θ 120 degrees or more,
Experiments have revealed that it is possible to prevent malfunctions that extend significantly to the outside. In addition, the practically preferable pattern width W of the drawer part is 4≧
W/-≧1.5, but the preferable value of W is the preferable pattern width of the gap forming part of the hairpin pattern 20 -=1
．． It is also related to the bubble diameter d=0.4 to 1.6 μm and the bubble diameter used. In addition, the opening angle θ is practically 120° to 18
0° is preferred. In this example, the bubble diameter used is d=o, 8 μm, and W/W
=1.5. In other words, the pattern @ - = 3 μm, the pattern width W of the drawer portion = 4.5 μL, and the opening angle θ is θ
Good results were obtained at =125°. Embodiment 2 FIG. 2 shows an example of a bubble detector according to another embodiment of the present invention. By improving the shape and structure of the magnetoresistive pattern 30, the malfunction described in FIG. 8 can be avoided. This prevents Note that the conductor patterns 20 and 40 are omitted in this figure because the drawing becomes complicated. In FIG. 2, the feature is that the shape of the magnetoresistive pattern 30 has been devised, and the pattern shape of the lead line portion A or B has been changed from the conventional linear pattern to a U-shape [second
It is distinctive in that it is bent into a shape shown in Figure 2 (a)) or an L-shape (Figure 2 (b)). By bending them into a U-shape as shown in Figure 2(a) and an L-shape as shown in Figure 2(b), these parts are magnetized by the rotating magnetic field HR. The generated bubble expansion magnetic fields HPA and HPB described in FIG. 8 are cut off. Note that one or more of these U-shaped or L-shaped patterns are provided in at least one of the lead line portions A and H, and one or more of these U-shaped or L-shaped patterns are provided in the non-ion implantation region STR.
Be sure to exist and form within. As a result, in this part,
Malfunctions in which the bubble is stretched outward are stopped. Embodiment 3 FIG. 3 shows an example of a bubble detector according to another embodiment of the present invention in which the shape of the magnetoresistive pattern 30 is modified in the same way as in FIG. 2. Add auxiliary pattern S to part A or part B of the leader line in question.
It is distinctive in that P is added. FIG. 3(a) shows an auxiliary pattern SP extending from the leader line of the magnetoresistive pattern 30 on a straight line perpendicular to the pattern 30, and FIG. 3(b) shows an auxiliary pattern SP extending on the extension line of the pattern 30. A configuration is shown in which auxiliary patterns Sp are arranged on each leader line. Note that the width of the practical auxiliary pattern Sp is
The pitch is approximately equal to the width of the pattern 30, and when multiple pieces are arranged, the pitch is equal to or within twice the width of the pattern 30.
In addition, the protrusion amount Q is about 2 to 4 times the bubble diameter d used.
More preferably, it is about twice as large. This auxiliary pattern Sp is formed simultaneously with the formation of the magnetoresistive pattern 30 in the same process. Further, this auxiliary pattern Sp is formed by arranging one or more cross patterns so as to be substantially perpendicular to the lead line portion 30A or B portion. This auxiliary pattern SP is magnetized by the rotating magnetic field HR and generates a magnetic field H5. This magnetic field Hs acts to stop the malfunction of the bubble being stretched outward. As a result, malfunctions can be prevented. Embodiment 4 FIG. 4 shows the leader line of the magnetoresistive pattern 30 in pattern 3.
2 shows a bubble detector having a structure in which a leader line extends linearly on an extension line of 0. Although this is an extremely simple configuration, the bubble does not protrude from the gap g of the conductor pattern 20 when the bubble expands or expands, so no unnecessary bubbles remain during the bubble extinguishing operation. Although the embodiments of the present invention have been described above, it goes without saying that the present invention can be applied in the same manner to detectors further combining the present inventions illustrated in FIGS. 1 to 4 above. . [Effects of the Invention] According to the present invention, as described above, it is possible to prevent malfunctions in which the bubbles that are expanded and expanded upon bubble detection protrude outside the effective area of the conductor pattern through which the bubble extinguishing pulse current flows. Therefore, this makes it possible to reliably realize the bubble extinguishing operation of the bubble detector and prevent the read information from being destroyed. 4)

[Brief explanation of drawings]

1, 2, 3, and 4 are plan views of essential parts of a bubble detector showing an embodiment of the present invention, respectively; FIG. 5 is a plan view of essential parts of a conventional bubble detector pattern; FIG. 6, FIG. 7, and FIG. 8 are plan views of essential parts of the bubble detector, each schematically showing the bubble extinguishing malfunction for explaining the bubble extinguishing malfunction. Explanation of symbols> 10... Ion implantation bubble transfer path, 20.4
0... Hairpin type conductor pattern, 30... Magnetoresistive pattern, 21.22... Root of hairpin type conductor pattern, 12... Ion implantation region, STR... Non-ion implantation region, HR. ...Rotating magnetic field, Sp...Auxiliary pattern of magnetoresistive pattern.

Claims (1)

[Scope of Claims] 1) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, a lead wire at the base of a hairpin conductor pattern through which a pulse current for expanding magnetic bubbles is passed. A magnetic bubble device comprising a pattern width W and a conductor pattern width of the hairpin portion ω, where W is at least 1.5 times ω. 2) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, the opening angle θ of the lead wire at the base of the hairpin conductor pattern through which a pulsed current for expanding the magnetic bubble flows is at least 120. A magnetic bubble device consisting of ゜. 3) A magnetic bubble device having an ion implantation transfer path and a current stretch type magnetic bubble detector, in which the pattern of the lead line portion of the magnetoresistive pattern is U-shaped or L-shaped. . 4) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, an auxiliary pattern made of the same material as the magnetoresistive pattern is arranged in the lead line portion of the magnetoresistive pattern. A magnetic bubble device consisting of. 5) In a magnetic bubble device having an ion implantation transfer path and equipped with a current stretch type magnetic bubble detector, a lead line of the magnetoresistive pattern extends linearly on an extension line of the magnetoresistive pattern. A magnetic bubble device made by