Mössbauer Study of Amorphous Fe₇₅P₁₅C₁₀

Amorphous ferromagnet Fe₇₅P₁₅C₁₀ has been studied by Fe⁵⁷ Mössbauer spectroscopy from 4.2 K to 1 100 K. In the amorphous state, the hyperfine field H_(eff)(T) decreases with temperature much more rapidly than that of crystalline Fe. Furthermore H_(eff)(T) decreases as BT^(3/2) at low temperatures indicative of spin wave excitations. The value of B is anomalously large. T_c = 619 ± 2 K is found to be sharply defined. Crystallization occurs at about 710 K. The subsequent crystalline phases consist of α-Fe (T_c = 1 040 K), Fe₃P (T_c = 715 K) and Fe₃C (T_c = 490 K)