PERMALLOY THIN-FILM MAGNETIC SENSORS

An introduction to the theory of the anisotropic magnetoresistance effect in ferromagnetic thin films is given, ending in a treatment of the minimalization of the free energy which is the result of the intrinsic and extrinsic anisotropies of the thin-film structure. The anisotropic magnetoresistance effect in long strips is reviewed. Attention is given to problems like the formation of domains and measures like biasing and linearization. The paper concludes with a description of some applications which are being developed by the authors: (1) an analyser for the stray field of recording heads; (2) a sensitive magnetometer; (3) an accurate absolute angle detector; and (4) an absolute (linear) position detector.