JPS6237980A - Ferromagnetic reluctance apparatus - Google Patents

Abstract

PURPOSE:To manufacture a compact ferromagnetic reluctance apparatus readily by a simple constitution, by providing a thin film coil on an insulating substrate, and providing a ferromagnetic reluctance element in the coil so that the direction of magnetic lines of force agrees with the longitudinal direction. CONSTITUTION:On an insulating substrate 10 comprising glass and the like, many parallel conductors 31 are formed at a constant interval and coated with an insulating film 33. Thereafter, a ferromagnetic reluctance element 20 is formed on the film 33. Then, the element 20 is covered with an insulating film 35. The insulating films 33 and 35 at both end parts of each conductor 31 and at both end parts of the element 20 are removed. The end parts of the conductors 31 are connected with an upper conductor 39, and a thin film coil 30 is formed. At the same time of the formation of the conductor 39, terminals 41, 43 and 45 are formed. A current is conducted through the coil 30, and a bias magnetic field is imparted to the element 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ferromagnetic magnetoresistive device with a bias magnetic field.

[Prior Art] Conventionally, a magnetoresistive element using a ferromagnetic thin film has good magnetic sensitivity, so it has been used as a reproducing head for digital recording and a magneto-electric conversion element for a rotation sensor. However, as shown in the characteristic diagram of FIG. 5, in which the horizontal axis represents the external magnetic field strength and the vertical axis represents the resistance value, this magnetoresistive element has a Barkhausen jump (dashed line portion 90.92) and hysteresis characteristics. Distortion of detection output due to (section 9
4) etc., the characteristics of A are unstable. Therefore, a method has been proposed to correct the unstable characteristics of the detection output by applying a bias magnetic field in the longitudinal direction of the magnetoresistive element (the direction of the easy axis of F41 conversion).

Usually, this bias magnetic field is created using a permanent magnet. That is, a permanent magnet is accurately pasted near the magnetoresistive element, taking into consideration the direction of the magnetic field.

[Problems to be Solved by the Invention] However, since it is necessary to accurately determine and affix the permanent magnets to 1r2litfl, the production f1 cannot be maintained.
Therefore, the manufacturing cost becomes high. Also, there was a drawback that it was not possible to reduce the size very much because of the attachment of the Socket IB.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a ferromagnetic magnetoresistive device that overcomes the problems mentioned above.

[Means for Solving the Problems] The ferromagnetic magnetoresistive device of the present invention includes an insulating substrate, a ferromagnetic magnetoresistive element that is provided on the insulating substrate-F and whose electrical resistance changes according to the strength of the surrounding magnetic field. , an @ film coil formed in a coil shape of 1110 near the ferromagnetic magnetoresistive element of the insulating substrate-F and generating a magnetic field of strength according to the applied current; the ferromagnetic magnetoresistive element; and the thin film coil. and a connection terminal provided on each of the.

Ferromagnetic magnetoresistive element of the present invention: 1. Instead of using a conventional permanent magnet, a thin film coil is formed, and a necessary bias magnetic force is generated by passing a current through the thin film coil.

The insulating base-3 plate constituting the ferromagnetic magnetoresistive device of the present invention is a member that holds other components and has predetermined electric withstand characteristics and current withstand characteristics. With this insulating board and one piece (
For example, glass substrates, Reramix M roots, synthetic resin substrates, etc. (Y) can be used as they are.

A ferromagnetic magnetoresistive element is an element that has a magnetoresistive effect in which the electrical resistance value changes depending on the strength of the field in the presence of a magnetic field. This magnetoresistive effect includes a physical effect caused by the material and a shape effect caused by the Hall electric field. To obtain a small magnetoresistive material, N1-C,o is usually used as a material. The ferromagnetic magnetoresistive element is formed as a thin film having a rectangular shape, for example, on the insulating substrate.

A thin film coil is provided near this ferromagnetic magnetoresistive element.
I'm happy. Here, the C thin film coil is made by compressing the loop formed by the winding wire into an elliptical shape rather than a perfect circle. Specifically, when the spring is cut along a plane passing through the central axis, it is divided into a lower part and an upper part, each consisting of a large number of parallel line segments. Each of the coil line segments in the lower part is formed into a straight line and formed on the substrate surface.

After that, an insulating layer is formed thereon, and then an upper part is formed above A, and the line segments of the upper part and the lower part are electrically connected, so that the whole is formed into a thin plate-like coil shape. This thin film coil and this ferromagnetic magnetoresistive element are placed at a distance such that the magnetic field generated by this thin film coil causes a resistance value of the ferromagnetic magnetoresistive element to change by a predetermined value or more due to the relative distance between the thin film coil and this ferromagnetic magnetoresistive element. need to be placed.

In order to make effective use of the magnetic field generated by this thin film coil, it is desirable that this ferromagnetic magnetoresistive element be located at the center of this coil. Or, if the central axis of this thin film coil and this ferromagnetic magnetoresistive element are rectangular,
In the case of a rod-shaped element, it is preferable that the element be relatively positioned so that the longitudinal direction of the element is parallel to the element.

The connection terminals are terminals that are electrically connected to each of the thin film coil and the ferromagnetic magnetoresistive element. It is desirable that this connection terminal be formed opposite to the formation of the thin film coil described above. A voltage that energizes the thin film coil is applied to the terminal connected to the thin S-1 coil, and a voltage signal, for example, corresponding to the external magnetic field is extracted from the terminal of the ferromagnetic T4 magnetoresistive element.

[Function] The insulating substrate holds the ferromagnetic magnetoresistive element, the thin film coil, and the connection terminal. This insulating substrate is placed within the magnetic field to be detected. When a current is applied to a terminal connected to a thin film coil, a magnetic field corresponding to the current is generated around the thin film coil. Therefore, this vAs causes a bias magnetic field to be applied to this ferromagnetic magnetoresistive element in its axial direction (longitudinal direction). Therefore, the signal taken out from the terminal connected to this ferromagnetic magnetoresistive element can be taken out as a signal that uniquely corresponds to the magnetic field, regardless of the magnetic field strength of the magnetic field to be detected. Further, even when the magnetic field strength is near zero, a phenomenon such as Barkhausen jump does not occur because this bias magnetic field is applied.

[Example] = 6 - Hereinafter, the ferromagnetic magnetoresistive device of the present invention will be described in detail based on specific examples. Fig. 1 is a plan view showing the structure of the ferromagnetic magnetoresistive device of the same embodiment, and Fig. 2 is a cutaway view including the central axis of the magnetoresistive element G'J in Fig. 1. FIG.

The ferromagnetic magnetoresistive device includes an insulating substrate 10, a ferromagnetic magnetoresistive element 20 (hereinafter abbreviated as magnetoresistive element 20), and a thin film.
30 and connection terminals 41, 43, and 45.

Hereinafter, the overculm in which the magnetoresistive rope 20 and the membrane coil 30 are formed will be explained in detail.

First, a large number of diagonal lower conductors 31 are formed parallel to each other at regular intervals on the upper right side of the -1-plane of the insulating substrate 10 as indicated by the broken line in FIG. 1, and then these lower conductors 31 are It is formed so as to be covered with an insulating film 33. Then, a magnetoresistive element 20 using a Ni--Co alloy ferromagnetic material is formed on one and two parts of this insulating film 33.

Furthermore, this magnetoresistive element 20 is formed so as to be covered with an insulating film 35. Thereafter, the portions of the insulating films 33 and 35 covering both ends of the lower conductor 31 and both ends of the magnetoresistive element 20 are etched to remove those portions of the insulating film. Next, connect the end of the lower conductor 31 exposed by removing the insulating film with the opposite end of the lower conductor 31 that meets the upper surface of the insulating film 35. Then, an upper conductor 39 is formed parallel to the base at a constant interval and has a diagonal shape downward to the right as shown by the solid line in FIG. As a result, a thin film coil 30 is formed in which a large number of square conductors 31 and a large number of upper conductors 39 are connected to each other at both ends thereof. Note that at the same time as forming the L portion conductor 39, the terminals 41, 43.
Form 45. In the ferromagnetic magnetoresistive device configured in this way, the thin film coil 30 is energized by the voltage applied to the connection terminals 41 and 43, so that the magnetoresistive element 2o
A magnetic field is applied in its longitudinal direction. When the direction and magnitude of the magnetic field to be detected changes, the voltage signals appearing at the connection terminals 43 and 45 are graphed as a characteristic diagram such as a curve 50 in FIG. 3. In addition,
In FIG. 3, the axis shows the strength of the magnetic field to be detected, and the vertical axis shows the voltage generated at both ends of the magnetoresistive element 20.

According to this embodiment, the magnetoresistive element 2o is the thin film coil 30.
Since the longitudinal direction of the magnetoresistive element 20 and the direction of the magnetic field lines obtained by the thin film coil 30 are precisely parallel, hysteresis and Barkhausen jump as shown in FIG. It has been resolved. Therefore,
The magnets can be accurately positioned and pasted like in conventional devices.
There's no need to cry. Therefore, it is possible to realize a highly productive ferromagnetic magnetoresistive device that is small and inexpensive.

In addition, as shown in the characteristic diagram of FIG. 4, the magnetoresistive element 20
If the component in the transverse direction of the magnetic field applied to is thicker than a predetermined value (if the characteristic curve 50 shown in FIG. 3 is In the case of the characteristic diagram in FIG. 4, the characteristic curve 51
is the characteristic surface Ii! 50, it has moved to the right by a movement width D51.

[Effects of the Invention] According to the present invention, a ferromagnetic magnetoresistive device is composed of an insulating substrate, a ferromagnetic magnetoresistive element, a thin film coil, and a connecting terminal. At both ends of the resistive element, a signal that corresponds uniquely to the detection slip resistance is obtained. Therefore, unlike conventional devices, there is no need to stick a permanent magnet in the vicinity of the ferromagnetic magnetoresistive element in consideration of its direction, which improves productivity and improves the accuracy of ferromagnetic detection. A resistance device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the structure of a ferromagnetic magnetoresistive device according to a specific embodiment of the present invention, and FIG. 2 is a cross section taken along a plane including the central axis of the magnetoresistive element in FIG. 1. It is a diagram. Figures 3 and 4 are characteristic diagrams that do not show the relationship between the magnetic field to be detected obtained by the same embodiment device and the signals appearing at both ends of the magnetoresistive element. FIG. 6 is the same characteristic diagram when the magnetic field applied in the lateral direction becomes larger than a predetermined value. FIG. 5 is a characteristic diagram showing the relationship between the magnetic field to be detected and the signals appearing at both ends of a magnetoresistive element, which was used to explain the prior art. 10...Insulating substrate 20...Ferromagnetic magnetoresistive element 30...Thin film coil 41.43.45...Connection terminal Patent applicant Nippondenso Co., Ltd. Agent Patent attorney Hirotoshi Okawa Patent attorney Akio Maruyama No. Figure 1 Figure 2 Figure 3 ΔP Tato Sound 5 gl X Figure 5 Kuto It

Claims (2)

[Claims] (1) An insulating substrate, a ferromagnetic magnetoresistive element provided on the insulating substrate and whose electrical resistance changes depending on the strength of a surrounding magnetic field, and a thin film coil disposed near the ferromagnetic magnetoresistive element on the insulating substrate. A ferromagnetic device comprising: a thin film coil formed in a shape and generating a magnetic field with a strength according to the applied current; and a connection terminal provided on each of the ferromagnetic magnetoresistive element and the thin film coil. Magnetoresistive device. (2) The ferromagnetic magnetoresistive device according to claim 1, wherein the ferromagnetic magnetoresistive element is located at the center of the thin film coil.