J. Phys. IV France 08 (1998) Pr2-19-Pr2-22
Influence of the fabrication conditions on the high frequency magnetic response of melt spun Fe73.5Si13.5B9Nb3Cu1L. Pascual1, C. Gómez-Polo2, M. El Ghannami1 and M. Vázquez1
1 Instituto Magnetismo Aplicado (UCM-RENFE), and Instituto de Ciencia de Materiales (CSIC), P.O. Box 155. 28230 Las Rozas, Madrid, Spain
2 Departamento de Física, Universidad Pública de Navarra, Campus de Arrosadia. 31006 Pamplona, Spain
The aim of this work is to analyze the influence of the fabrication conditions on the magnetic properties of Fe73.5Si13.5B9Nb3Cu1 melt-spun nanocrystalline ribbons. Different initial structures, amorphous and partially crystalline, have been obtained during the rapid solidification procedure. The structural characterization shows that a decrease in the quenching rate through a reduction in the tangential wheel velocity, gives rise to a partially crystalline state, characterized by the appearance of a textured α-FeSi nanocrystalline phase. The occurrence of the crystalline fraction in the initial as-cast state gives rise to a magnetic hardening with respect to the amorphous sample casted at higher quenching rate. However, the evolution of coercivity under thermal treatments is roughly independent of the initial structure. Moreover, a detailed analysis of the ac susceptibility as a function of annealing temperature shows that the ribbon obtained at lower quenching rate presents higher susceptibility values in the optimum magnetic state (Ta = 550°C, 1 h) in a wide range of driving frequency (up to 100 kHz).
© EDP Sciences 1998