Mössbauer spectroscopic study of FeAl_1−x Co _x

Abstract

We report the results of a Mössbauer study of the alloy sytem FeAl_1−x Co _x forx ≥ 0.3 at temperatures down to 83 K. Magnetic splitting is observed forx ≥ 0.35 at all temperatures. However, forx=0.3, no splitting is observed at room temperature, and superparamagnetic behavior occurs at LN₂ temperature. The magnetically split spectra are fitted each with a distribution of hyperfine fields and the average hyperfine field$\bar B_{hf}$ as a function of temperature is obtained. The variation of$\bar B_{hf}$ withT is explained using the model of magnetic clusters with collective magnetic excitations from which the saturation hyperfine field and the magnetic anisotropy energy for these clusters are obtained. Also, the results are discussed using the model of random atomic distributions, and the agreement between the calculated and the experimentally obtained distributions of hyperfine fields is found improve asx increases.