CRITICAL PHENOMENA OF AMORPHOUS Fe13Ni67.2P4.5B15.3 ALLOYS

Results of the magnetization measurements performed on the amorphous Fe13Ni67.2P4.5B15.3 alloy in the temperature range 1.5 to 300 K in fields up to 40 kOe are reported. The behaviour near the Curie temperature is found to obey second-order phase transition laws with critical indices: β=0.39±0.02;γ=1.56±0.06; δ=5.20±0.1, and the ferromagnetic Curie temperature Tc = (180.4 ± 0.2)K. Within experimental error the critical indices satisfy the scaling law relationship γ=β(δ-l). The data satisfy the magnetic equation of state characteristic of a second-order phase transition in the temperature range 168 to 192 K. Above 270 K, the paramagnetic susceptibility obeys the Curie-Weiss law. From the Curie constant c, we obtain the effective magnetic moment peff=3.19 μB.