The effect of adding a bit of Fe to Ag?Ge?Se system

B. ARCONDO; M. A. UREÑA; M. ERAZÚ; J. A. ROCCA; M. FONTANA

HYPERFINE INTERACTIONS

Springer Netherlands

Año: 2008 vol. 182 p. 137 - 147

0304-3843

Ag-Ge-Se system is an easy glass former in a wide composition range not far from the Se corner of the equilibrium phase diagram. The existence of a liquid miscibility gap impacts on the glass morphology where Ag-rich zones alternate with Ag depleted ones which size depends on composition. In order to analyze the short range order, 0.5 at. % Fe was added as a probe in the synthesis stage.  Mössbauer spectra of these glasses were obtained at room and lower temperatures. Two types of environments were observed. The corresponding Debye temperatures, and the fraction of Fe atoms in each environment were determined. Additionally, magnetic moment was measured as a function of temperature and applied magnetic field. From m(H) and m(T) curves it is evident that the magnetization of the glasses has two components, i.e., a blocked one even up to room temperature that saturates at low field, and a paramagnetic one which does not saturate even at the largest applied field.    The Mössbauer spectroscopy results are discussed and correlated to the morphology and magnetic behavior of these glasses.