Magnetic properties of partially crystallized Fe₇₈B₁₄Si₈ amorphous alloys

Abstract

Surface crystallization in ferromagnetic amorphous ribbons produces a perpendicular magnetic anisotropy, with consequent improvement of some magnetic properties. The development of a crystalline phase in amorphous Fe₇₈B₁₄Si₈ has been checked by means of different techniques on both surfaces of the ribbons. The effect of thermal treatments on power losses has been determined. Isothermal measurements of the power losses show a minimum displaced towards low times at high annealing temperatures. A more complete crystallization process produces an increase in losses and a general deterioration of soft magnetic properties. The effect of partial crystallization in the amorphous matrix on the power losses is discussed in terms of the current models.