Observation of magnetic hysteresis loop of the perminvar type in worked Co-based amorphous alloys

Abstract

Magnetic hysteresis loops were measured for polished Co-based Co-Fe amorphous alloys using a longitudinal Kerr effect apparatus. Squared and constricted, or so-called perminvar, loops were observed when the direction of the applied magnetic field was parallel and normal to the direction of polishing in the specimen surface, respectively, where magnetostriction constant λs of the specimen takes a small positive, zero, or fairly small negative value. This feature is remarkably emphasized for the specimen with λs ≃0, while it is inverted for the specimen with a relatively large negative value of λs, at least with λs ≃−1.4×10−6. That is, the easy direction of magnetization is changed into the normal direction to the one of polishing, and the perminvar loop is observed in the direction of polishing.