Studies of inhomogeneity effects on properties of superconducting materials / Estudo da influencia de inomogeneidades nas propriedades de materiais supercondutores

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In this work we study the physical properties of bismuth samples. Crystalline bulk bismuth, in the rhombohedral phase, is not superconducting, but, in the cubic phase, for example (obtained under pressure), in films and in the amorphous phase, may present superconducting transition. We observed superconductivity in a bismuth virgin powder and in samples prepared upon annealing this powder. Due to the small volumetric superconducting fraction we suspect that the superconductivity is related to the sample s surface. Moreover, the superconducting properties are strongly dependent upon the annealing conditions (these samples may be either superconducting or not). We also performed magnetotransport measurements in a single-crystalline bismuth sample and observed a characteristic feature of this material, namely, metal-insulator transition driven by applied magnetic field

ASSUNTO(S)

supercondutividade granular metal-insulator-metal transitions transições metal-isolante-metal bismuth granular superconductivity bismuto

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