LOW-TEMPERATURE MAGNETIC-BEHAVIOR OF AMORPHOUS AND NANOCRYSTALLINE FE73.5CU1NB3SI13.5B9 ALLOYS

The initial susceptibility, virgin magnetization curves, hysteresis loops, and saturation magnetization are measured in the temperature range from 80 to 290 K for the Fe73.5Cu1Nb3Si13.5B9 alloy in the as-quenched state and after annealing. It is stated that domain wall movements are dominant magnetization processes in nanocrystalline alloys. The coercivity distinctly increases after cooling crystallized samples to 80 K. In the temperature range from 80 to 230 K, the saturation magnetization obeys a T3/2 law for all samples. No necessity for introducing a T5/2 term is observed up to 230 K. The spin wave stiffness constant increases with annealing temperature and time.