Soft magnetic properties of nanocrystalline Fe75−xCoxZr8Nb2B15 (x=5, 10, 15) alloys

Abstract Soft magnetic properties of melt spun Fe 75− x Co x Zr 8 Nb 2 B 15 alloys have been investigated in terms of partial nanocrystallization by proper thermal treatment. The spin wave stiffness constant, D , was estimated from the temperature dependence of the magnetization at low temperature. The Curie temperature, T c , is enhanced with increasing Co content. In particular, D / T c , which measures the range of the exchange interaction, are roughly independent of Co concentration. The incremental permeability ratio (PR) shows the drastic changes of soft magnetic properties as a function of annealing temperatures. Soft magnetic samples are obtained from the sample with x =10 annealed at 500°C and the sample with x =15 annealed at 400°C as clearly distinguishable from the sharpness of PR as well as its magnitudes.