Fe environments in Fe doped Ge-Se based glasses

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

La Plata, Argentina

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

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> 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.