The influence of composition and aging on the Curie temperature of metallic glasses

The influence of composition, particularly glass formers P,B,C, and Si and transition metals Ni and Co, on the Curie temperature Tcand the change in Tcupon isochronal annealing of Fe based glasses is reported. Magnetic order-disorder transition in a "liquid" state is manifested for some (Fe,Co) glasses. The Tcvs. y curves of some Fe100-yGyglasses are seen to exhibit a maximum. Here G represents glass formers. Tcincreases by 2 ∼ 4 K with annealing just above Tcfor all glasses observed. With further increase in annealing temperature, Tccontinues to increase for B and Si containing glasses, while for glasses containing P and C, Tctends to decrease. The influence of metalloid addition and alloying among Fe, Co and Ni on Tcof metallic glasses will be interpreted in the framework of the Bethe curve.