JPH06196772A - Magnetic resistance element - Google Patents

Abstract

PURPOSE:To make a resistance temperature coefficient of a magnetic resistance element small by using a ternary alloy of Cr, Al, and Fe for a ferromagnetic metal thin film of the magnetic resistance element and by setting the composition of the film within the specific range. CONSTITUTION:A resistor pattern 2 which is formed of a ferromagnetic metal thin film is manufactured by depositing an alloy film which has the composition of Cr 17%, Al 13.5% and Fe for the rest and by patterning the allay film by photolithography and by forming electrodes 3 and a protective film 4 and then by heat-treating at 300 deg.C. When the ferromagnetic metal thin film is heat-treated in vacuum at 300 deg.C for one hour, a temperature coefficient of a magnetic resistance is very much improved and becomes very small, +-50ppm/ deg.C or smaller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a magnetoresistive element which is a magnetoelectric conversion element using a ferromagnetic metal thin film.

[0002]

2. Description of the Related Art A ferromagnetic metal thin film is deposited on one surface of an electrically insulating substrate, a zigzag resistor pattern is formed by a photoetching process, and the resistor patterns are arranged orthogonally to each other and they are arranged in series at a midpoint. Wired and used as a voltage terminal. When a magnetic field is applied perpendicularly to the longitudinal direction of the resistor, the resistance value of the resistor decreases and the resistance values of other resistors increase.

Fe-Ni type alloys and Ni-Co type alloys have been used for conventional magnetoresistive elements.
The system has a small magnetoresistive effect, and the Ni-Co system has a large magnetoresistive effect but a large hysteresis. The Fe-Ni system and the Ni-Co system had a small magnetoresistive effect in a low magnetic field of 50 Oe or less. In addition, the temperature coefficient of electric resistance of the Fe-Ni system and the Ni-Co system is large and 2500-3500 PPM / ° C.
Met.

[0004]

As described above, in the conventional magnetoresistive element, the ferromagnetic metal thin film is made of Fe-Ni system or Ni-C.
Since an o-based alloy was used, the temperature coefficient of electric resistance was particularly large. An object of the present invention is to propose a magnetoresistive element capable of solving these problems.

[0005]

In order to solve this problem, the magnetoresistive element of the present invention comprises a ferromagnetic metal thin film containing Cr and A.
A ternary alloy of 1 and Fe is used, and its composition is set to Cr15 to 20.
%, Al 3-4% Residual Fe. Further, in the second invention, this ferromagnetic metal thin film was heat-treated at 250 to 350 ° C. in the atmosphere. The third invention is characterized in that a resistor pattern of the ferromagnetic metal thin film made of the ternary alloy is formed on a substrate, and an electrode and a protective film are provided on the resistor pattern. .

[0006]

[Operation] According to the present invention, it is possible to stably detect magnetism regardless of changes in ambient temperature.

[0007]

Embodiment 1 In the embodiment shown in FIG. 1, 1 is an electrically insulating substrate, and 2
Is a pattern formed by etching a zigzag pattern by photolithography on a ferromagnetic metal thin film deposited by vacuum deposition or sputtering on the substrate surface,
Reference numerals 3 and 4 respectively denote an electrode and a protective film provided on the resistor pattern 2.

A resistor pattern 2 made of a ferromagnetic metal thin film is formed by depositing an alloy film having a composition of Cr 17% and Al 3.5% residual Fe, forming a pattern by photolithography, and thereafter forming an electrode 3 protective film 4. Heat treatment at ℃ is performed. The thin film has a thickness of 8000 A and the resistor pattern has a width of 50 μm.

Such a ferromagnetic metal thin film is placed in vacuum 30
As shown in Table 1, the temperature coefficient of magnetic resistance in the case of the heat treatment of holding at 0 ° C. for 1 hour is small as shown in Table 1, and the degree of improvement is large.

[0010]

According to the present invention, the temperature coefficient of resistance of the magnetoresistive element is as small as 1/100 of that of the conventional product, and the fluctuation of the output due to the temperature change is small, and stable measurement can be performed particularly in a low magnetic field of 50 Oe or less. .

[Brief description of drawings]

FIG. 1 is a side view of a magnetoresistive element of the present invention.

FIG. 2 is a plan view of a magnetoresistive element of the present invention.

[Explanation of symbols]

 1 substrate 2 thin film magnetoresistive pattern 3 electrode 4 protective film

[Table 1]

Claims (3)

[Claims] 1. A weight ratio of Cr15 to 20%, Al3
Ferromagnetic metal thin film consisting of ~ 4% and residual Fe, with temperature coefficient of electric resistance around room temperature plus or minus 50PPM
A magnetoresistive element having a temperature of / ° C or less. 2. A weight ratio of Cr 15 to 20% and Al 3
〜4%, the remaining Fe has a ferromagnetic metal thin film, and this ferromagnetic metal thin film is 250 to 350 in air or vacuum.
A magnetoresistive element characterized by being subjected to heat treatment at ℃. 3. A weight ratio of Cr15 to 20%, Al3
A magnetoresistive element characterized in that a resistor pattern of a ferromagnetic metal thin film consisting of ˜4% of residual Fe is formed on a substrate, and an electrode and a protective film are provided on this resistor pattern.