MOSSBAUER STUDY OF AN AMORPHOUS MAGNETIC SOLID CONTAINING CR

A Cr-containing transition metal based amorphous magnetic solid (Fe32Ni36Cr14P12B6) has been studied by Fe57 Mössbauer spectroscopy in both its amorphous and crystalline states. The magnetic ordering temperatures of TC=249, 254, and 238 K have been determined for samples from three batches. In the amorphous state at T>TC, well-defined quadrupole spectra are observed. At 4.2 K, the hyperfine-field distribution P(H) is characterized by a two-maxima function of H. It is shown that the high-field component is due to Fe with mainly Fe and Ni as neighbors, whereas the low-field component originates from Fe atoms with Cr neighbors. The temperature dependence of P(H) is studied at various temperatures and unusual features have been observed. In both the amorphous and the crystalline states of the sample, a noticeable amount of Fe is found to be weakly coupled. This is consistent with the results of the magnetic measurements and provides an explanation of the resistivity anomaly. © 1979 The American Physical Society.