Influence of the changes of free electron density on electrical and magnetic properties of the Co<inf>70</inf>Fe<inf>5</inf>Si<inf>10</inf>B<inf>15</inf> amorphous alloy

Abstract

In this study we present the results on structural relaxation of the Co70Fe5Si10B15 amorphous alloy investigated by measuring the thermo-electromotive force (TEMF) during isothermal annealing (for 600 s). A mechanical junction of the investigated alloy and a copper conductor has been constructed for measuring the thermo-electromotive force (ε). Annealing was performed at temperatures T1=430°C, T2=460°C and T3=480°C which are about 50 to 100°C lower than the crystallization temperature. At these temperatures structural relaxation occurred only in the amorphous alloy. The activation energy E=224 kJ/mol and rate constants k1=6.66·10-5 s-1, k2=33·10-5 s-1 and k3=76·10-5 s-1 at temperatures T1, T2 and T3, respectively, have been determined for the process. Each isothermal annealing has been followed by determination of the relative change of the electronic state density at the Fermi level as Δn1/n=2.36%, Δn2/n=3.21% and Δn3/n=9.80%, respectively.