Magnetic properties and structural evolution of FINEMET alloys with Ge addition

The influence of Ge addition on the devitrification process into nanocrystalline structure and on the magnetic properties of Finemet alloys has been examined. Fe73.5Si13.5-xGexNb3B9Cu1 (x = 10 and 13.5) ribbons were obtained by the melt spinning technique and their structure was investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Hysteresis loops of the ribbons after heating at increasing temperatures, T-A up to full devitrification of the amorphous precursors were performed to study the magnetic properties of the different alloys. The enhancement of the Curie temperature of the amorphous phase (T-c(am)) in order to improve the magnetic properties at high temperatures of these materials has been broadly studied during the last few years. Our results show that the addition of Ge leads to an increases around 45 K of the T-C(am) of Finemet alloy without lowering the M-S of the system. (C) 2004 Elsevier B.V. All rights reserved.