Hyperfine Fields and Magnetic Moments in the Fe–Rh System

Publisher Website
Google Scholar
Abstract
Hyperfine fields and isomer shifts of Fe57 in the Fe–Rh system have been measured by the Mössbauer technique in the composition range between 0 and 52 at. % Rh. When the Rh concentration exceeds 25%, chemical ordering of CsCl type develops and two distinct hyperfine fields are observed, corresponding to Fe on Fe sites (Fe I) and Fe on Rh sites (Fe II). For example, Hi(I) = 277 kOe and Hi(II) = 384 kOe in an alloy containing 48% Rh. Neutron diffraction study of this alloy gives μFeI = 3.2 μB and μRh = 0.9 μB. It is suggested that Fe II, which is surrounded by 8 Fe nearest neighbors, may have a smaller magnetic moment than Fe I despite its higher hyperfine field. These results are consistent with a model in which the polarization of conduction electrons is negative and its magnitude is reduced when rhodium replaces iron as nearest neighbors.