JPS6158287A - Magnetoelectric conversion element - Google Patents

Abstract

PURPOSE:To eliminate the deformation of the waveform of output signal and to relax the Barkhausen noise by a method wherein the folded parts of the magnetoelectric conversion element in a jigzag form are made of a non-magnetic and conductive metal. CONSTITUTION:When a signal magnetic field Hex is made to act orthogonally to the longitudi nal direction of the magnetosensitive resistors B of a magnetosensitive element 1, a magnetoresistance change is not generated in the folded parts A in the same direction as that of the Hex, because the folded parts are made of a non-magnetic and conductive metal, and the change is generated in the magneto-sensitive resistors B only. Accordingly, in case that length l of each resistor B is short and even in case the product of the number of folded times and the width WL of each folded part A is large, a signal to indicate a resistance change, which corresponds accurately to the intensity of the Hex, can be obtained in a termi nal 4. Moreover, when a terminal 3, the terminal 4 and a terminal 5 are also made of the same material as that of the folded parts A, the saturated magnetic fields of the element 1 and an element 2 are decreased to the saturated magnetic fields Hsb only of the magnetosensitive resistors B and the distortion of the waveform of output signal is relaxed. Furthermore, no intrusion of a magnetic domain into the magnetosensitive resistors B from the folded parts A is generated. As a result, the Barkhausen noise is also relaxed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magnetoresistive magnetoelectric conversion element composed of a ferromagnetic thin film.

<Prior Art> A magnetoresistive magnetoelectric conversion element converts the strength of a magnetic field into an electrical signal by utilizing the magnetoresistive effect in which the electrical resistance of a ferromagnetic metal changes depending on a magnetic field.

N1-co constituting this magnetoresistive magnetoelectric conversion element
t For ferromagnetic metals such as Ni-Fe and MrA, 20X10 to 40X depends on the thickness of vsM'A.
Since the specific resistance of 10 Ω is extremely low, the film thickness and width of the element used as the magnetoresistive element are adjusted accordingly. However, considering the limited element dimensions, it is difficult to obtain a high resistance value by forming only one magnetically sensitive element, and in practice, it is difficult to obtain a high resistance value by forming only one magnetically sensitive element. By increasing the length, the necessary resistance value is obtained.

FIG. 2 shows an example of a conventional magnetoelectric transducer. Magnetically sensitive element 1' and magnetically sensitive element 2' each have a plurality of ferromagnetic thin films arranged in the same direction, including magnetosensitive resistance part B' and folded part A.
′ is formed in a zigzag-like folded pattern. A power supply terminal 3' is formed at one end of the magnetically sensitive element 1', and an output signal extraction terminal 4' is formed at the connection between the magnetically sensitive element 1' and the magnetically sensitive element 2'. A grounding terminal 5' is formed at the other end of 2'. ! The three-magnetic element 1' and the magnetically sensitive element 2' are arranged such that the directions of their respective magnetically sensitive resistance portions B' are perpendicular to each other. Note that the directions of the magneto-sensitive resistance parts B' are not perpendicular to each other, but are, for example, 4
It may be a direction forming an angle of 5 degrees, or basically any angle.

Magnetically sensitive element 1' and magnetically sensitive element 2' differ only in the angle formed by the direction of magnetically sensitive resistance part B', and have the same shape, dimensions, and configuration. Therefore, hereinafter, magnetically sensitive element 1'Let's talk about.

In FIG. 2, the folded portion A' is formed integrally with the magnetosensitive resistance portion B' from a ferromagnetic metal thin film.

In this case, when the external magnetic field (signal magnetic field) ′ and magneto-sensitive resistor B′, the directions of resistance change are opposite to each other, resulting in a small amount of change in the overall resistance of magneto-sensitive element 1′. If there are many parts A',
Alternatively, if the length l of the magnetically sensitive resistive portion B' is short, the influence of the folded portion A' cannot be ignored, causing a reduction in the operational accuracy of the element.

On the other hand, the line width of the magnetic resistance part B' is WE, and the folded part A'
Let wL be the width of is expressed by the following formula.

HsA=Hk+4ycMsWL/T-=
(L) Hsa= Hk + 4 rc M s WE
/T-(2) (In Equations 11 and (2), Hk is an anisotropic magnetic field and 4πMs is magnetization, both of which are determined by the materials used. Also, T is the thickness of the ferromagnetic thin film.

As is clear from Figure 2, since WL>WE, T
From equations 1) and 2, the relationship H8A<H2S is established. The graph in FIG. 3 shows the rate of change in resistance with respect to the external magnetic field Hex at the folded part A' and the magnetosensitive resistance part B' at this time. In FIG. 3, a is the resistance of the folded part A'. The rate of change and b indicate the rate of change in resistance of the magneto-sensitive resistor section B'. From this figure, it can be seen that the folded section A' and the magneto-sensitive resistor section B'
It is clear that the saturation magnetic field is different between

In this way, since the saturation magnetic field H8A of the folded part A' and the saturation magnetic field Hsa of the magnetosensitive resistance part B' are different, the length l of the magnetosensitive resistance part B' is short (and the number of folds and the folded part A
' If the pattern shape has a large product of width WL, H8A
The mixture of Hsa and Hsa distorts the output signal waveform of the element.

<Objective of the Invention> The present invention has been made in view of the above circumstances, and its object is to provide a magnetoresistive effect type magnetoelectric transducer in which the adverse effects of the folded portion of the magnetic sensing element are eliminated.

<Structure of the Invention> In the present invention, the ferromagnetic metal thin film is formed with a ferromagnetic metal thin film having a magnetoresistive effect, and the length of the φ magneto-sensitive resistor part is formed by forming the ferromagnetic metal thin film into a zigzag folded shape. The magnetoelectric transducer is characterized in that the folded portion of the element having the above-mentioned zigzag folded shape is formed with a non-magnetic and conductive fully bent shape.

<Example> An embodiment of the present invention will be described below.

FIG. 1 shows the configuration of a magnetoresistive magnetoelectric transducer. The magnetically sensitive element 1 and the magnetically sensitive element 2 each have a zigzag folded pattern consisting of a plurality of magnetically sensitive resistance parts B and folded parts A in the same direction. formed into a shape. A power supply terminal 3 is formed at one end of the magnetically sensitive element 1, an output signal extraction terminal 4 is formed at the connection between the magnetically sensitive element 1 and the magnetically sensitive element 2, and the other end of the magnetically sensitive element 2 is formed. A grounding terminal 5 is formed at the portion. Magnetic sensing element 1
and the magneto-sensitive element 2 are arranged so that the directions of their respective magneto-sensitive resistance portions B are orthogonal to each other. Note that the angle formed by the magnetically sensitive resistance portion B of the magnetically sensitive element 1 and the magnetically sensitive resistance portion B of the magnetically sensitive element 2 may be arbitrary, as in the prior art example described above.

In FIG. 1, the magnetically sensitive resistance portions B of the magnetically sensitive element 1 and the magnetically sensitive element 2 are made of Ni-Co.

It is formed of a ferromagnetic metal thin film having a magnetoresistive effect, such as Ni-Fe. On the other hand, the folded portion A of the zigzag folded pattern of the magnetically sensitive element 1 and the magnetically sensitive element 2 is made of a thin film of a nonmagnetic and conductive metal such as AI, Cu, or Au, as shown by diagonal lines in the figure. is formed. The magneto-sensitive resistance parts B are connected to each other by these non-magnetic and conductive metal thin films. Furthermore, the power supply terminal 3, the output signal extraction terminal 4, and the grounding terminal 5, which are not originally constituted as a magneto-sensitive resistor, are also formed of the above-mentioned non-magnetic and conductive metal thin film.

Now, when an external magnetic field (signal magnetic field) Hex acts in a direction perpendicular to the longitudinal direction of the magnetically sensitive resistance part B of the magnetically sensitive element 1, as shown by the arrow in the figure, the folded part A in the same direction as this magnetic field Hex Since it is formed of a nonmagnetic and conductive metal, the folded portion A does not cause a change in magnetoresistance, and only the magnetoresistive portion B causes a change in magnetoresistance. Therefore, even when the length β of the magnetosensitive resistance part B is short, or even when the product of the number of folds in a zigzag pattern and the width W of the folded part A is large, the resistance changes accurately in accordance with the strength of the magnetic field Hex. A signal indicating this will be obtained at the output signal extraction terminal 4.

In addition, by forming the folded portion A and the terminals 3.4.5 with a non-magnetic and conductive metal thin film, the saturation magnetic field in the magneto-sensitive elements 1 and 2 is the same as the saturation magnetic field Hs of the magneto-sensitive resistance portion B.
e, and different saturation magnetic fields do not coexist as in the conventional case, so distortion of the output signal waveform is alleviated.

Furthermore, as a ripple effect of the present invention, Barkhausen jump, which is always a problem in the magnetization process of magnetic materials, can be improved at the same time. This Barkhausen jump is thought to occur when the magnetic domain begins to extend from the folded part A' in Figure 2 when an external magnetic field is applied, and this enters a part of the magnetically sensitive and resistive part B'. In addition, by using the configuration of the present invention, Barkhausen noise is also alleviated.

<Effects of the Invention> As explained above, in the present invention, since the folded portion of the magnetoelectric conversion element having a zigzag folded shape is formed of a non-magnetic and conductive metal, it can accurately respond to the magnetic field. Not only can an output signal be obtained, but also distortion of the output signal waveform can be eliminated. Furthermore, Barkhausen noise is also alleviated.

[Brief Description of the Drawings] Fig. 1 is a plan view showing one embodiment of the present invention, Fig. 2 is a plan view showing a conventional example, and Fig. 3 is the relationship between the external magnetic field and the rate of change in resistance of the magnetic sensing element. This is a graph showing. 1.2... Magnetically sensitive element A... Folded part B... Magnetically sensitive resistor part Patent applicant Sharp Co., Ltd. Agent Patent attorney Nishi 1) New third diagram) Four-peak field H-x

Claims (1)

[Claims] (1) In a magnetoelectric transducer that is composed of a ferromagnetic metal thin film having a magnetoresistive effect, and has a zigzag folded shape to increase the length of the magnetosensitive resistance part formed of the ferromagnetic metal thin film. . A magnetoelectric transducer, characterized in that the folded portion of the element having the zigzag folded shape is formed of a nonmagnetic and conductive metal.