Desenvolvimento de um detector de alta eficiência para espectroscopia Mossbauer de elétrons de conversão (CEMS) a baixas temperaturas (<20 K) e testes em bicamadas Fe/ (EUxPb1-x)Te / Development of a highly efficient conversion electron Mossbauer spectroscopy (CEMS) detector for low temperature (<20 K) measurements and tests on Fe/ (EuxPb1-x)Te bylayers

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The 57Fe Mössbauer spectroscopy is a nuclear, non-destructive technique used for the investigation of structural, magnetic and hyperfine properties of several materials. It is a powerful tool in characterizing materials in physics, metallurgy, geology and biology field areas, especially magnetic materials, alloys and minerals containing Fe. Lately, the Conversion Electron Mössbauer Spectroscopy (CEMS) is widely used in making studies on ultra-thin magnetic films, as well as other nanoestructured materials. In case of magnetic nanostructures, low temperature (LT) studies are especially important due to the possibility of dealing with superparamagnetic effects. In this work it was developed a CEMS measurement system for low temperatures (<20K) based on a solid-state electron multiplier (Channeltron) and an optical cryostat (Model SVT-400, Janis Research Co, USA), from which the project was originally conceived at the Applied Physics / Mössbauer Spectroscopy Department from University of Duisburg-Essen, Germany. The LT-CEMS system was fully built, tested and successfully applied in a preliminary characterization of Fe/(EuxPb1-x)Te(111) bilayers with use of a 15 Å, 57Fe probe layer, with reasonable results at sample temperatures as low as 8 K.

ASSUNTO(S)

efeito moessbauer moessbauer effect iron 57 nondestructive testing ensaios não destrutivos materials testing fisica da materia condensada ferro 57 magnetic materials materiais magnéticos

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