抄録
Magnetization measurements have been made for Fe–Ni Invar alloys in high magnetic fields up to 180 kOe at high temperatures up to 850 K. In contrast to the case of pure Fe and pure Ni, M2–H⁄M curves for Invar alloys are hardly described by Landau’s phenomenological equation in a high field region above 100 kOe. Namely, the M2–H⁄M curves are bent upward in high fields. Furthermore, it was observed that the magnetization curve is deviated upward from linearity by applying high fields in a higher temperature region. This additional magnetization over the usual one was reconfirmed by means of the transversal magnetoresistance effect measured with a pulse high field up to 300 kOe. This anomalous magnetization induced by a high field is considered to be due to re-polarization of low spin states of constituent Fe atoms.
