Magnetic phase transition in amorphous Fe sub 73.5 Cu sub 1 Nb sub 3 Si sub 13.5 B sub 9 alloy

Critical exponents, the corresponding amplitudes and the universal amplitude ratios have been obtained for the amorphous Fe sub 73.5 Cu sub 1 Nb sub 3 Si sub 13.5 B sub 9 alloy from detailed bulk magnetization measurements performed in the critical region near the magnetic phase transition temperature. The critical exponents determined are beta , gamma , gamma ' and delta , among which beta describes the temperature dependence of the spontaneous magnetization, gamma (T > T sub C ) and gamma ' (T < =T sub C ) describe the temperature dependence of the zero-field susceptibility, and delta describes the field dependence of the magnetization at the Curie temperature, T sub C . The values of T sub C obtained in the present investigation match very well those reported in the literature. The critical exponent values are very close to those theoretically predicted for the three-dimensional Heisenberg spin system.