Overview of magnetoresistors
A magnetoresistance is a resistor made based on the magnetoresistance effect. It is a novel sensing element that can change its resistance under the action of external magnetic field (including the change of the intensity and direction of the applied magnetic field). It can be divided into two categories: semiconductor magnetic sensitive and ferromagnetic metal thin film magnetoresistance.
The various physical effects (Hall effect, magnetoresistance effect) of the magnetic field acting on the conductor were found in the metal as early as 1879-1883, but the effect was not significant and has not been widely used for a long time. After the advent of semiconductors, new compound semiconductor materials with high mobility, such as indium antimonide (InSb), were developed in the second half of the 1950s, which also promoted the research, development and application of Hall devices and magnetoresistive devices.
The development of semiconductor magnetoresistance began in the early 1960s. In this respect, the German company Siemens is more authoritative, followed by Japan, the United States, the Soviet Union, Western Europe and other countries. In the mid-1960s, there were commodities sold. Because of its advantages like ordinary resistors, it has two terminals, simple structure, high sensitivity, and convenient installation. Its application is more common.
The ferromagnetic metal film susceptor is a thin film type magnetic susceptor device made of a ferromagnetic alloy material, and its action principle is the magnetoresistance effect of the ferromagnetic body, which is different from the semiconductor susceptor except for the magnetic field. The intensity sensitivity (same point as the semiconductor susceptor) is also very sensitive to the direction of the magnetic field (unlike the semiconductor susceptor). Since the film is not a semiconductor material but a ferromagnetic alloy, it has a small temperature coefficient and is stable in performance and high in sensitivity, and has been commercialized and put into practical use.
The ferromagnetic metal film susceptor is a magnetic sensor developed by Sony Corporation of Japan in the early 1970s. It developed rapidly in the past ten years. It can be used to form many new magnetic sensors for measuring micro-displacement, angle, speed, flow, pressure, etc.