From Magnetic Sensors Corporation
AMR magnetic field sensors were briefly introduced in the December 1998 issue of Sensors ("A New Perspective on Magnetic Field Sensing "). Now we take a closer look at the way they work and where they are used.
Michael J. Caruso and Tamara Bratland, Honeywell, SSEC
Carl H. Smith and Robert Schneider, Nonvolatile Electronics, Inc.
Magnetoresistive sensors are made of a nickel-iron (Permalloy) thin film deposited on a silicon wafer and patterned as a resistive strip [13]. The film's properties cause it to change resistance by 2%3% in the presence of a magnetic field. In a typical configuration, four of these resistors are connected in a Wheatstone bridge to permit measurement of the magnitude of the magnetic field along the direction of the axis. The bandwidth is usually in the 15 MHz range. The reaction of the magnetoresistive effect is very fast and not limited by coils or excitation frequencies.
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REFERENCES [1] uti?, I., J. Fabian, and S. Das Sarma, "Spintronics: fundamentals and applications," Rev. Mod. Phys., Vol. 76, No. 2, 2004, pp. 323 410. [2] Daughton,...
