Estudo de anisotropia magnética nos compostos intermetálicos ErFe3Hx e (Er1-x Gdx)Fe3 por espectroscopia Mössbauer no 57Fe

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

1983

RESUMO

The magnetic anisotropy in the ternary hydrides ErFe3Hx and in the pseudobinary (Eri _ x Gd x )Fe3 compounds has been studied by 57 Fe Mdssbauer spectroscopy. ErFe3 shows a spin reorientation from basal plane above 47 K to the C axis below this temperature. The direction of the magnetization is the result of a competition between the crystal field anisotropy at the Er sites, the magnetic exchange interaction and the iron sub-lattice anisotropy. The results show that this spin reorientation in the hydride at 240 ±5 K, as independent of the hydrogen concentration. For the pseudobinary (Er i _ x Gd x )Fe3 a decrease in the reorientation temperature is observed as the Gd concentration increases. Above 20 at%, no reorientation occurs. For the hydride, the results are described as resulting from changes in the crystal field anisotropy and magnetic exchange interaction associated with the presence of hydrogen. Some suppositions are made concerning the hydrogen sites occupation. The decrease in the reorientation temperature with the Gd concentration can be described by a single particle model in which the free energy is calculated in terms of the magnetic exchange and relevant crystalline electric field interactions.

ASSUNTO(S)

fisica da materia condensada anisotropia magnetica : ligas efeito mossbauer

ACESSO AO ARTIGO

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