JPS61123188A - Magnetoelectric device using magnetic thin-film having planar magnetoresistance effect - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetoelectronic device using a magnetic thin film having a planar magnetoresistive effect, which is applied to a T+L coder for detecting the bubble axis of a bubble memory and the speed of an electric motor. This invention relates to a conversion device.

[Conventional technology]

Using the planar (in-plane) magnetoresistive effect of a magnetic thin film, the
Reference literature: K, E, Kuljk et al. rTHE B
Question B plate POI, E, A LINEARMAGNET
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IEEE Transactions on Magn
eties t vat, Mag-11Jf65
# 'September 1975, proposed. This magnetoelectric conversion element has a current of 4 with respect to the axis of easy magnetization.
When the current flows at an angle of 5 degrees and a magnetic field is applied in the plane at an angle of 45 degrees, the resistance value of the magnetoresistive element changes almost linearly with the magnitude of the magnetic field. The output voltage is extracted differentially. This basic configuration is shown in FIG. 4 or 5. That is, the magnetic thin film 11 of /4'-malloy, which is a nickel-iron (NiFe) alloy,
The electrode 13 for short-circuiting the lines of electric force using a conductive material is set at 45 degrees (angle R8T' (
(Fig. 4)) or 135 degrees (Fig. 5). When such a configuration is used, the direction of current flow (indicated by arrow l) is the short circuit type 4i1ij
13, the direction of the current is 45 degrees or 135 degrees with respect to the axis of easy magnetization, and the magnetic field H is in the direction perpendicular to the axis of easy magnetization within the plane of the magnetic thin film 11 (indicated by arrow H).
, a magnetoelectric transducer is obtained in which large resistance orthogonalization occurs due to changes in the magnetic field.

[Problems to be Solved by the Invention] However, the magnetoelectric transducer having the above-mentioned configuration has a problem in that the end portion of the magnetic thin film 110 in the width W direction (for example, SW in FIG.
Since the parallel arrangement of the two strip electrodes 13 is disrupted in the area surrounded by There is a problem that the angle is not 45 degrees or 135 degrees with respect to the longitudinal direction of the thin film 11. Therefore, as shown by the broken line in FIG. 3, the output characteristic is not linear with respect to the strength of the magnetic field, and as the in-plane magnetic field increases, the incremental value of the busy output decreases. The present invention aims to improve the above-mentioned problems in magnetoelectric transducers.

Therefore, an object of the present invention is based on the idea of changing the shape of the electric force line short-circuiting electrode at the widthwise end of a strip-shaped magnetic thin film, and the present invention is based on the idea of changing the shape of the electric force line short-circuiting electrode at the widthwise end of the magnetic thin film. The lines of electric force are aligned as perpendicularly to the longitudinal direction of the short-circuiting electrode as possible and do not spread out, so that the relationship between the magnetic field and the resistance value of the magnetoelectric transducer is linear, that is, the output voltage with respect to the magnetic field. The object of the present invention is to obtain a magnetoelectric transducer that changes linearly.

[Means for solving problems]

The present invention provides a device that improves the above-mentioned problems, and the means thereof is in the form of a strip-like thin film, having an axis of easy magnetization in the longitudinal direction, and approximately 45 degrees or 135 degrees with respect to the longitudinal direction. An electrode for short-circuiting the lines of electric force is provided at an angle of approximately 9 to the longitudinal direction of the nucleus within the thin film plane
In a magnetoelectric transducer using a magnetic thin film having a planar magnetoresistive effect in which a magnetic field is applied in the 0 degree direction, the electric field lines are short-circuited! The planar magnetoresistive effect in which the poles are pressed to increase the distance between adjacent electrodes in a portion of the adjacent electrodes excluding the portion where adjacent electrodes facing each other in a direction perpendicular to the longitudinal direction of the electrodes is present. This is done by a magnetoelectric transducer using a magnetic thin film.

[Effect]

The present invention uses a magnetoelectric transducer configured as described above to supply a certain current between electrodes for shorting lines of electric force! - If the magnetic thin film of the magnetoelectric transducer is placed so that it receives a magnetic field in the plane perpendicular to the axis of easy magnetization, the direction of the current at the widthwise end of the magnetic thin film will be relative to the longitudinal direction of the shorting electrode. The shorting electrodes are improved to be vertically aligned so that the output voltage obtained from the shorting electrode has a linear relationship to the strength of the external magnetic field.

〔Example〕

1 and 2 are plan views of a magnetoelectric transducer element of a magnetoelectric transducer using a magnetic thin film having a planar magnetoresistive effect as an embodiment of the present invention. In Figure 1,
The magnetic thin film 11 is strip-shaped, has a thickness of approximately 300 angstroms or more, a width w-b%1o to 50 micrometers, and is made of 100% Malloy, with an axis of easy magnetization in the direction of arrow M. It is being This magnetic thin film 11 has a large resistance value change in response to a magnetic field perpendicular to the easy magnetization axis (indicated by arrow H) within the plane of the magnetic thin film 110 when current is applied in a direction of 45 degrees or 135 degrees to the easy magnetization axis. bring about.

Therefore, in order to pass current in the 45-degree direction, a plurality of short-circuiting electrodes 12 (indicated by vertical lines in the figure) for shorting the lines of electric force are formed on the magnetic thin film 11 using a method such as vapor deposition of gold, Au, etc. It adheres to the surface. The electrode 12 has a strip-like planar shape, and its longitudinal direction is 45 mm with respect to the direction of the axis of easy magnetization of the magnetic thin film 11 (in this example, the direction of the long side AA' of the rectangular magnetic thin film 11). It's moderate. Regarding one electrode 120 shown in FIG. 1, the vertices of the quadrilateral shape are designated as B, C, and Di, and the point B is on the side AA', and the dot is on the magnetic thin film 11 facing the side AA'. Let F be the intersection of the extension of the line connecting point B and point C with the other side, and let G be the intersection of the extension of the line connecting point B and point E and side AA'. do. Furthermore, in Figure 1, points B, C, D, and E
A point corresponding to the point C of the electrode 12 adjacent to the left side of the electrode 12 surrounded by is set as a point 21, and a point corresponding to Bk is set as a point,
A point corresponding to point E on the electrode 12 adjacent to the right side is called a point N1, and a point corresponding to point E is called a point.

Angle ABC and angle ALP are arranged to form an angle of 45 degrees. In the longitudinal direction of the electrodes (C
The portions where adjacent electrodes exist (PL, DE, CB) facing in the direction perpendicular to the B direction (PD direction).

The electrodes of the parts (EB, CD parts) excluding the CN part) are as follows:
Compared to conventional electrodes, some parts (KGB, CFD parts are removed) so that the distance between adjacent electrodes is larger.
Ru. In this example, electrodes are used in which points E and B and points C and D are connected by straight lines, but electrodes in which they are connected by appropriate curves may also be used.

In a device using such a magnetic thin film 11 with a plurality of electrodes 12 arranged, when a current is passed between the electrodes 120, the direction of the current, that is, the direction of the electric lines of force is mostly in the longitudinal direction of the electrodes. The direction is perpendicular to the opposite direction. In particular, in this embodiment, the spread of electric lines of force at the ends of the electrode in the width W direction, which is the case with conventional electrodes, is reduced. In this way, the direction of the current can be kept at 45 degrees with respect to the axis of easy magnetization of the magnetic thin film 11, making it possible to improve the characteristics as shown in the characteristic diagram of FIG.

The characteristic diagram in Figure 3 shows the in-plane magnetic field (Oersted) on the horizontal axis,
The output voltage (millidelts) is plotted on the vertical axis, and the broken line shows the characteristics of the conventional type, and the solid line shows the characteristics of the present embodiment. This shows that the linearity of the output voltage with respect to changes in the in-plane magnetic field is improved in the device of the example. Note that the output voltage is the value when a current of 5 milliamps and 4 amperes is passed through the magnetic thin film 11.

The plan view of the magnetoelectric conversion element in Figure 2 shows another example in which the current is applied in a direction of 135 degrees with respect to the direction of the axis of easy magnetization, and the other examples are the same as the element in Figure 1. The same is true. When the magnetoelectric transducer shown in FIG. 1 is used, the resistance value of the element increases as the magnetic field increases (ie, a positive element), but the resistance value of the magnetoelectric transducer shown in FIG. 2 decreases (ie, a negative resistor).

FIG. 5 shows a plan view of a conventional magnetoelectric transducer corresponding to the magnetoelectric transducer shown in FIG.

〔Effect of the invention〕

According to the present invention, the direction of current flow is aligned as perpendicularly as possible to the longitudinal direction of the electric field shorting electrode even at the ends in the width direction of the magnetic thin film of the magnetoelectric transducer, and the electric field lines As a result, it is possible to obtain a magnetoelectric conversion device in which the relationship between the magnetic field and the resistance value of the magnetoelectric conversion element is linear, that is, the output voltage changes linearly with respect to the magnetic field.

[Brief explanation of drawings]

FIG. 1 is a plan view of a magnetoelectric transducer of a magnetoelectric transducer using a magnetic thin film having a planar magnetoresistive effect as an embodiment of the present invention, and FIG. 2 is a plan view of another example of the magnetoelectric transducer shown in FIG. FIG. 3 is a characteristic diagram comparing the characteristics of the device shown in FIG. 1 with those of a conventional device, and FIGS. 4 and 5 are plan views of a conventional magnetoelectric transducer. 11...Magnetic thin film, 12...'E for shorting electric lines of force
Pole, 13: Conventional short-circuiting electrode for electric lines of force. Figure 1 Figure 2 Figure 3 0, 10. 20 30 40.5
Zero in-plane magnetic field (Oe) Figure 4 Figure 51 Procedural amendment (method) Date of April I, 1985

Claims (1)

[Scope of Claims] 1. A strip-shaped thin film having an axis of easy magnetization in its longitudinal direction, and having an angle of approximately 45 degrees or 135 degrees with respect to the longitudinal direction for short-circuiting lines of electric force. In a magnetoelectric transducer using a magnetic thin film having a planar magnetoresistive effect in which an electrode is provided and a magnetic field is applied in a direction approximately 90 degrees to the longitudinal direction within the thin film plane, for shorting the lines of electric force. The distance between adjacent electrodes is increased in a portion of the electrodes adjacent to each other excluding a portion where an adjacent electrode facing perpendicularly to the longitudinal direction of the electrode is present, and a current flows between the electrodes. A magnetoelectric transducer using a magnetic thin film having a planar magnetoresistive effect, characterized in that when energized, most of the lines of electric force are aligned in a direction perpendicular to the longitudinal direction of the electrode. 2. The device according to claim 1, wherein the distance between adjacent electrodes increases linearly toward the ends.