JPS61232687A - Magnetoresistance element - Google Patents

Abstract

PURPOSE:To improve the sensitivity of a magnetoresistance element by sequentially alternately determining the angles of connecting portions of a plurality of long pieces aligned in parallel and a plurality of short pieces for connecting the long pieces in series of zigzag-shaped resistance pattern at angles between both to 45 deg. and 135 deg., thereby canceling the variation in the magnetoresistances. CONSTITUTION:A resistor pattern 6 is formed of a plurality of long pieces 11, 12... arranged in parallel, and a plurality of short pieces 15, 16... for connecting the long pieces in series. The pattern 6 is so determined sequentially at angles A-F alternately at 45 deg. and 135 deg. in such a manner that an angle A between the long piece 11 and the short piece 15 is 45 deg., an angle B between the pieces 15 and 12 is 135 deg., an angle C between the pieces 12 and 16 is 45 deg., an angle D between the pieces 16 and 13 is 135 deg., an angle E between the pieces 13 and 17 is 45 deg., and an angle between the pieces 17 and 14 is 135 deg.. thus, the short pieces 15, 16 of both ends of one long piece 12 are disposed perpendicularly to one another. Accordingly, when a magnetic field is rotated in the element surface, the variation in the resistances of the short pieces disposed at both ends becomes reverse to be canceled to one another to eliminate the cancel of the sensitivity of the element.

Description

[Detailed Description of the Invention] A1 Objective of the Invention E1. INDUSTRIAL APPLICATION FIELD This invention relates to a magnetoresistive element that utilizes the anisotropic magnetoresistive effect of a ferromagnetic material.

E2. Conventional magnetoresistive elements are made by depositing a thin film of ferromagnetic material on a flat insulating substrate by vacuum evaporation or sputtering, forming a resistor pattern by photolithography and etching, and then forming a resistor pattern. The electrodes were formed in the same manner as the electrodes were formed. Since the electrical resistance of this magnetoresistive element changes depending on the direction of the magnetic field applied to the element, it is used to measure physical quantities such as the rotation and movement of a magnet.

The ferromagnetic resistance effect can be achieved by using a ferromagnetic material T4III fl with a magnetoresistive effect such as Nt, Go, Fe or an alloy thereof.
) as shown in Figure 4, and a large magnetic field (B) that sufficiently saturates the magnetoresistive effect is applied in the plane of the thin film at an angle θ with the current (i). This is a phenomenon in which the resistance value R of the magnetic material changes according to θ. Angle θ is 4
If the resistance value at the time of 5 is Ro+the resistance change caused by the rotation of the magnetic field is ΔR, then the resistance R is expressed by the following equation (1).

R=Ro+%ΔRCO32θ...(1) Magnetic field (B
) direction, that is, the angle θ, and this relationship between resistance R is a waveform that repeats every 1806 times as shown in Figure 5, and even if the current (i) and magnetic field CB) are reversed, the resistance value R remains the same. becomes.

In order to increase the resistance value of the element, a practical magnetoresistive element has a zigzag-like (folded) resistance structure consisting of a large number of long pieces arranged in parallel and a number of short pieces that connect these long pieces in series. It forms a body pattern, and is published in Japanese Patent Application Laid-Open No. 50-2898.
9 and Sokai No. 54-1'485'77. A part of this zigzag resistor pattern is shown in Figure 6, where the long piece (2) and the short piece (4) are arranged at right angles, and the short pieces (3) and (4) are parallel. If an element is formed by connecting n long pieces (2) with a resistance value of R and n short pieces (3) with a resistance value of r, the total resistance value of the element is n(R→r). Become.

The resistance value R of the long piece is R=Ro+%ΔRcos 2θ, and the resistance value r of the short piece is r − r, 10% Δrcos 2 (θ→−90), so R'+r=Ro →−r, l 10V2(△R-∆r)co
s2θ...(2) The rate of change in magnetoresistance of this element is (ΔR-Δr
) / (Ro −1−ro ) is 1, which is smaller than the rate of magnetoresistance change ΔR/R of the material itself shown in FIG. The reason for the decrease is that the short pieces are arranged at right angles to the long pieces, so that the resistance value of the short pieces changes in a direction that reduces the resistance change of the long pieces, depending on the direction θ of the magnetic field.

In the above conventional technology, the long piece and the short piece are at right angles, but US Pat.
No. 40□5355 specifies that the angle between the strip and the 45° or 135°
A magnetoresistive element is shown that forms a zigzag resistor pattern with short pieces arranged at an angle D. Since all the short pieces of this material are parallel, the change in resistance of the short pieces cancels out the change in resistance of the long pieces, making the sensitivity smaller than the sensitivity of the material itself.

E3. Problems to be Solved by the Present Invention - As mentioned above, in the prior art, the resistance change of the short pieces constituting the resistor pattern acts to reduce the resistance change of the long pieces, and all Since the short pieces are parallel, the effects of attenuation are additive and all work in a negative direction.

Therefore, there was a drawback that the sensitivity of the element was reduced.

The purpose of this invention is to reduce the drawbacks of the prior art by devising the arrangement of the short pieces relative to the long pieces that cause the main magnetic resistance change so that the short pieces cancel out the resistance changes caused by the short pieces.

1. Constituent row of invention 1. Means for Solving the Problems The magnetoresistive element of the present invention includes a zigzag-shaped resistor backbone formed of a plurality of long pieces arranged in parallel and a plurality of short pieces connecting the long pieces in series. The present invention is characterized in that the angle between the long piece and the short piece at the connecting portion thereof is set to 135° and ``A'' 45 degrees in sequence.

0-2° Effect According to the present invention, the short pieces located at both ends of one long piece of the resistor pattern constituting the magnetoresistive element form an angle of 90 degrees with respect to each other. Therefore, when the magnetic field rotates within the element plane,
Since the resistance changes of the short strips located at both ends are in opposite directions and cancel each other out, the sensitivity of the element is not diminished.

The change in resistance of the long piece itself due to the magnetic field is the same as in the prior art.

Row 3. Example In the example shown in FIG. 1, (5) is an insulating substrate, (6)
is a resistor pattern, (7) is another resistor pattern having long pieces arranged at right angles to the long pieces forming resistor pattern +61, +81. (91 and 00) are electrodes.

The resistor pattern (6) includes a plurality of long pieces (]I), (12), (13), (
+4)... and a plurality of short pieces (15), (16), (17), for connecting these long pieces in series.
It is composed of...

As shown in FIG. 2, this resistor pattern (6) has an angle A between the long piece (11) and the short piece (15) of 45°.
5) and the long piece (12) is 1351 long piece (12)
) and the short piece (16) is 457, the angle between the short piece (16) and the long piece (13) is 135', and the angle E between the long piece (13) and the short piece (17) is 45': Downstream between short piece (17) and long piece (14) is 135', angles A, B, C, ・
. . 45 and 135 are set alternately in the order of F.
Therefore, the short pieces (15) and (16) at both ends of one long piece (12) are arranged at right angles to each other.

In addition, in FIG. 2, the long pieces and short pieces are expressed as lines (straight lines) with no width for convenience of explanation, but in reality, they have a constant l] as shown in FIG.

In FIG. 3, the resistance values r of the short pieces (15) and (1,6) are r, -r. −L'AΔrcos 2 (October 35°)
It is. However, rD is the resistance value of the short piece (16) when the short piece (16) and the magnetic field I3 are at an angle of 45, and Δr is the resistance change of the short piece (16) when the magnetic field rotates.

Moreover, the resistance value rL of the short piece (17) is rz""
r, 1'AΔrcos 2 (θ→−45 et al.

Also, long pieces (II), (12), (1,3)
Since the resistance value R is R=Ro+'AΔRcos2θ, the sum R' of the resistance R of the long piece (12) and the resistance r7 of the short piece (16) is RT,=R+r,=Ro+r. +2ΔRcos2θ−
(2Δrsin2θ Similarly, the resistance R of the long piece (13) and the resistance r of the short piece (II)
Yo's sum RT, ba RT, -R+r, = Ro → r, + 'AΔRc
os2 θ−2Δrsin2 θ. If the number of long pieces and short pieces in the entire resistor pattern (6) is n, the total resistance is (R''['',
+R″r2) n/2=n (Ro +ro)
−1−−7−ΔRcos2 θ−−−! 3)
.

, 2, and the change in magnetic resistance of the short piece is canceled out by the state of the short piece, and the rate of change in magnetic resistance of the element consisting of the resistor pattern (6) is ΔR/ (Ro + r,,), which is the same as that of the conventional technique 6.
It is larger than (ΔR - Δr) / (Ro + r.) in the figure.

Normally, the rate of change in magnetoresistance ΔR/Ro of the material itself is about 5%, but in the prior art shown in FIG.
:], the rate of change in magnetoresistance is (ΔR−Δr)
/ (Ro + r,) = 0.0409, i.e. 4
．． 09%. On the other hand, in the case of the present invention, assuming that the resistor pattern is formed on the same substrate size, R
The ratio of and rz (or r yo) is 9: ], 414 f, r
Therefore, the rate of change in magnetoresistance as an element is ΔR/(
Ro + r,) = 0.05x9 / (9+1
．． 414)-〇,0432 That is, it is 4.32%, which is 0.0% lower than the conventional element's 4.09%.
The value is 23% larger.

C1 Effects of the Invention According to the invention, adjacent short pieces connected in series are at right angles to each other, and changes in magnetic resistance are canceled out, so that the sensitivity of the element is improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, with the insulating coating on the surface omitted. FIG. 2 is a diagram explaining the resistor pattern (6) in FIG. 1, and FIG. 3(a) (b+ is the first
A partially enlarged view of the resistor pattern shown in the figure and a diagram showing the angular relationship between the magnetic field B and the long and short pieces. Figure 4 is an oblique view explaining the magnetoresistive effect. Figure 5 is the one shown in Figure 4\magnetic field. FIG. 6 is a partially enlarged plan view of a conventional resistor pattern. (5)...Insulating substrate

Claims (1)

[Claims] In a zigzag resistor pattern formed by a plurality of long pieces arranged in parallel and a plurality of short pieces connecting the long pieces in series, the angle between the long pieces and the short pieces is sequentially alternated at the connection part between the long pieces and the short pieces. A magnetoresistive element characterized by having angles of approximately 45° and 135°.