Magnetism and point defect in B2-type CoFe alloys

Magnetic behavior of B2-type Co1−cFec alloys (0.4≤c≤0.6) is studied as functions of composition and quenching temperature. Obtained mean magnetic moment shows increase with composition up to c≈0.52 and then changes its slope. Furthermore, the moment decreases with quenching temperature in the B2-phase region, while it remains constant in the A2-phase region. The relation between the observed magnetic moment and the point defect properties is discussed. As a result, the change in the magnetic moment is found to be proportional to the square of the long-range order parameter. This relation is explained by noting the magnetic moment on Fe atom, which is assumed to depend on the number of nearest neighbor Co atoms.