Hyperfine field distribution in disordered binary alloys

Mossbauer measurements were made on the disordered binary alloys Ni 3 Fe NiFe and FeCo at different temperatures and the distribution of hyperfine magnetic fields has been evaluated using a model-independent method of analysis proposed by Window (1971). The full width at half-maximum of the P(H) distribution is found to remain constant for Ni 3 Fe with respect to temperature. It increases for NiFe but decreases for FeCo with increase of temperature. The full width at half-maximum is correlated to the exchange interaction and the measurements show that the range of exchange interaction is shorter in NiFe than in Ni 3 Fe. In FeCo all the atoms are found to have the same magnetic ordering temperature. The reduced value of the average field for NiFe is fitted to the Brillouin function.