Estudo de propriedades estruturais, magneticas e magnetocaloricas de compostos a base de Gd, Ge e Si / Study of structural, magnetic and magnetocaloric properties of Gd, GE e Si based compounds

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

This work presents the results from structural, magnetic and magnetocaloric studies about some compounds based on Gd, Ge and Si. Structural studies include optical and electronic microscopy analyses, besides X-ray diffraction. Magnetic analyses are limited to measurements of magnetization as a function of temperature and magnetic field. Using these techniques, the compounds are investigated under different processing conditions, such as: as-cast, heat-treated, powdered and sintered samples. Gd5Ge4 and Gd5Ge2Si2 compounds are also analyzed through magnetic measurements performed under hydrostatic pressure. We have inserted hydrogen atoms into Gd5Si4, Gd5G e2Si2 and Gd5Ge2,1S i1,9 compounds and substituted Sn for Ge and Si in Gd5Ge2Si2 compound. Thus, new families of materials were developed, which are also investigated in this work using the techniques mentioned above. Besides the experimental work, theoretical results are presented for the magnetocaloric effect using the Landau-Devonshire model. We also present phenomenological results for Gd5Ge2Si2 compound under hydrostatic pressure using the Coupling Magnetic-Lattice Model

ASSUNTO(S)

sintering hidrogenação pressão hidrostatica sinterização hydrostatic pressure metais de terras raras magnetocaloric effect efeito magnetocalorico hydrogenation rare earth metals

ACESSO AO ARTIGO

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