Magnetostriction measurements for amorphous wires

Novel accurate and stable measurement methods for the magnetostriction constant lambda /sub s/ and the induced anisotropy constant K/sub u/ are presented for amorphous wires. The two constants are theoretically expressed using a magnetization rotation model with or without tensile and compressive stresses. Values of flux densities B/sub s/, B/sub r/, and B/sub m/ are estimated, observing 60 Hz BH characteristics of the amorphous wire to which a compressive stress is applied in order to realize the magnetization rotation behavior. Measured variations of lambda /sub s/ and K/sub u/ of wires of different compositions for heat treatments with or without stresses are given. A figure of merit for stress sensor constitution is proposed as lambda /sub s/B/sub s//K/sub u/, a maximum value of which is obtained due to a compressive stress anneal for Fe-rich wires.<
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