Effect of thermal treatment on the magnetization processes of nanocrystalline Fe80Ge3Nb10B7 alloys

Abstract The dynamic magnetization processes of nanocrystalline Fe 80 Ge 3 Nb 10 B 7 alloys after annealing at different temperatures are studied through the permeability spectroscopy. Three steps of crystallization are found when amorphous Fe 80 Ge 3 Nb 10 B 7 alloys are heated from 300to 1200 K. The dominant magnetization process varies with different annealing temperatures. Domain wall bulging is the main magnetization mechanism under weak applied field. When the applied field exceeds pinning field H p , the depinning-involved domain wall displacement occurs. Different annealing temperature results in different H p . The lower value of μ ′ and high relaxation frequency after heating at 923 and 973 K are due to the strengthened domain wall pinning and the increase of magnetocrystalline anisotropy.