Anomalous Temperature and Field Dependences of Magnetocrystalline Anisotropy in Disordered Fe–Pt and Fe–Pd Invar Alloys

Abstract

The first magnetocrystalline anisotropy constant K₁ was determined by means of torque method for 26.5, 28.3, 29.9, 30.9, 33.2 at%Pt–Fe and 31.9, 34.2 at%Pd–Fe disordered alloys and the temperature and field dependences of K₁ of these alloys were compared with those of Fe–Ni Invar alloys. Anomalous temperature and field dependences of K₁ were found below room temperature for all Fe–Pt disordered alloys and for 31.9 at%Pd–Fe alloy in the low temperature region. These anomalous behaviors of K₁ seems to be caused by the contribution of uniaxial anisotropy of f.c.t. clusters.