Fe environments in Fe doped Ge-Se based glasses

ERAZU, M.; ROCCA, J.; CONDE GARRIDO, J. M.; MARIA ANDREA UREÑA; FONTANA, M.; ARCONDO, B.

La Plata, Argentina

Conferencia; XI Latin American Conference on the Applications of the Mössbauer Effect 2008 (LACAME 2008); 2008

GeySe1-y system is an extraordinary glass former for y≤0.43 atomic fraction. These glasses are floppy for y<0.20 and rigid for y>0.26 whereas in the composition range 0.20<y<0.26 these glasses are considered stress free as the irreversible component of enthalpy is meaningless [1, 2]. Several metals can be introduced in high concentrations in the composition of these chalcogenide glasses (above 25 at.% for Ag and alkali metals) and strongly modify their properties. On the other hand transition metals (3d and 4d) cannot dissolve easily for concentrations higher than 1 at. %. Mihai Popescu [3] suggests that the elements Fe, Co, Ni practically do not enter into the homogeneous glassy matrix. On the contrary, he proposes that Fe environments in Ge-Se based glasses correspond to the structural units Fe2GeSe4 and FeGe2Se4.In this work Fe environments in Ge-Se and Ag-Ge-Se bulk glasses doped with 0.5 at. % Fe are analyzed by Mössbauer spectroscopy and compared with those of the ternary compounds and FeSe. The intrinsic inhomogeneity of the structure of these glasses is corroborated employing Small Angle X-ray Scattering. In addition, magnetic characterization M(T), M(H) is performed.