Laboratorio Of Solidos Amorfos

Buenos Aires, Argentina

Laboratorio Of Solidos Amorfos

Buenos Aires, Argentina
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Erazu M.,Laboratorio Of Solidos Amorfos | Rocca J.,Laboratorio Of Solidos Amorfos | Fontana M.,Laboratorio Of Solidos Amorfos | Urena A.,Laboratorio Of Solidos Amorfos | And 2 more authors.
Journal of Alloys and Compounds | Year: 2010

Chalcogenide glasses have many technological applications as a result of their particular optical and electrical properties. Ge-Se and Ag-Ge-Se systems were recently studied and tested as new materials for building non-volatile memories. Following these ideas, thin films of Ge-Se and Ag-Ge-Se were deposited using pulsed laser deposition (PLD). Ag was sputtered over binary films (for a composition between 0.05 and 0.25 Ag atomic fraction) and photo-diffused afterwards. Thus, three kinds of samples were analyzed by means of Raman spectroscopy, in order to provide information on the short- and medium-range order: PLD binary films before Ag doping, after Ag doping and PLD ternary films. Before Ag doping, binary films exhibited Ge-Se corner-sharing tetrahedra modes at 190 cm-1, low scattering from edge-sharing tetrahedra at 210 cm-1, and Se chains at 260 cm-1 (stretching mode). However, after the diffusion process was complete, we observed an intensity reduction of bands centered at 210 cm-1 and 260 cm-1. The spectra of the photo-diffused films were similar to those of films deposited using a ternary target. Relaxation effects in binary glasses were also analyzed. Results were compared with those of other authors. © 2009 Elsevier B.V. All rights reserved.


Urena M.A.,Laboratorio Of Solidos Amorfos | Fontana M.,Laboratorio Of Solidos Amorfos | Piarristeguy A.,Charles Gerhardt Institute | Arcondo B.,Laboratorio Of Solidos Amorfos
Journal of Alloys and Compounds | Year: 2010

GexSe1-x system is a well-known glass former for x ≤ 0.43. The addition of third elements (i.e. Ag, Sb, and Sn) even up to high concentrations is possible without affecting its glass forming ability. These metals confer these glasses very particular properties. Ag-Ge-Se glasses are semiconductors for low Ag concentration whereas they are fast ionic conductors above 8 at.% Ag. The structure, thermal behaviour and transport properties of these glasses are analyzed. Metal doping is easily performed in chalcogenide glasses. It has been observed that, in contrast to crystalline semiconductors, their transport properties were not substantially affected as the valence bonds of the doping elements are completely saturated. The resource of doping with a 57Fe probe is widely employed in the materials study in order to characterize the short-range order of their structure by means of Mössbauer effect spectroscopy. These results are discussed and correlated to the structure and morphology of this chalcogenide system. © 2009 Elsevier B.V. All rights reserved.


Silveyra J.M.,Laboratorio Of Solidos Amorfos | Cremaschi V.J.,Laboratorio Of Solidos Amorfos | Cremaschi V.J.,CONICET | Vlasak G.,Slovak Academy of Sciences | And 3 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2010

Magnetostriction, dilatation and calorimetric measurements were performed on FINEMET type as-quenched and heat treated ribbons. Nb was gradually replaced by Mo in order to study the influence of the refractory elements exchange on several magnetostriction parameters. The results could be correlated with magnetic and structural transformations throughout thermal treatments and assured that the whole series is suitable for technical applications. © 2010 Elsevier B.V. All rights reserved.

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