Exchange correlation and magnetism in bcc Fe0.8Ni0.2 alloy

Abstract We investigate the magnetism and the electronic structure of body centred cubic, Fe 0.8 Ni 0.2 alloy. While the magnetic moment of pure Fe and the alloy in bcc phase are almost similar, the hysteresis loop exhibits soft magnetic behavior. Transport measurements exhibit hysteresis in cooling and heating cycles indicating possibilities of structural change in the alloy. Photoemission results exhibit signature of correlation induced effect in the core level spectra. The interaction parameters associated to the Ni electronic states are found to be influenced by the alloying presumably due to disorder induced effect. Fe 2 s core level spectra exhibit three distinct peaks due to exchange splitting and correlation of Fe 3 d electrons. The exchange splitting seems to remain unchanged in the temperature range studied in the alloy. Evidently, electron correlation and disorder is important to derive the complex electronic properties of this material. Our results establish that the magnetism and transport properties of Fe can be influenced significantly keeping the Fe moment unchanged via alloying with Ni, which is important for the applications of this material. Further studies are required to understand the resistivity anomaly and soft magnetism of this alloy.