Mn and Si influence on the hyperfine properties of the fcc and hcp phases in the Fe-Mn and Fe-Mn-Si systems

A study of the hyperfine properties of the fcc and hcp phases of the Fe-Mn and Fe-Mn-Si systems, performed on a systematic and accurate set of samples belonging to the 15 at% to 30 at% Mn and 0 at% to 12 at% Si composition ranges, is presented. The samples were characterized using Conversion Electron Moessbauer Spectroscopy. The evolution with the Mn and Si contents of the hyperfine parameters of both phases has been determined. A constancy of the isomer shift parameter of the hcp phase with both constituents of the alloy was observed. While constancy and a linear decrease of the isomer shift values of the fcc phase with Mn and Si, respectively, were determined. The magnetic hyperfine field of the fcc phase presents two different values depending on the Mn content in the binary system and a decrease with the addition of Si when the ternary alloy is considered. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)