CARACTERIZACÃO DAS PROPRIEDADES ESTRUTURAIS E MAGNÉTICAS DA SÉRIE SmFe1xMnxO3. / CHARACTERIZATION OF THE PROPERTIES STRUCTURAL MAGNETIC AND SERIES SmFe1 xMnxO3.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

10/02/2012

RESUMO

In this work we synthesized sample of the series SmFe1xMnxO3 , in which 1 x 0 whit variation of x = 0:1. Our main objective was the structural and magnetic characterization of the compounds. First, to the best of our knowledge, these samples were obtained by the combustion reaction method, with which we achieve success in obtaining unique polycrystalline phases, which were conrmed by the technique X-ray diraction . The diraction measurements were realized at room temperature with Rigaku diractometer having Bragg - Brentano geometry. The structural characterization indicates that the inclusion of Manganese in place of the Ion causes signicant changes in network parameters, but the volume remaining constant. These data were obtained through the renement of patterns using Rietveld method. For the magnetic characterization, we use the technique of DC magnetometry. The magnetic measurements as a function of temperature measurements as a function of magnetization and the magnetic eld were performed in a temperature range of 2K to 700K and magnetic eld range of 7T H 7T, respectively, using the MPMS magnetometer with SQUID detection and VSM magnetometer. The magnetic ordering of the sample 0 x 0:3 and x = 1 is reported in the literature for antiferromagnetic, the critic temperature (TC) of the ends of series agree with our data (670K for SmFeO3 and 57K for SmMnO3). To the intermediate sample, there is a reduction of TC with the increase of Manganese, due to weakening of the magnetic interactions caused by the insertion of the ion. Another important characteristic we emphasize in magnetization as a function of the temperature is a coexistence of the phases. We observed characteristics of a second magnetic transition, below of TC, that which can be re-associated with spin reorientation (SR), as is already known in SmFeO3, in which the SR occurs by changing the easy axis of magnetization (em T = 480K). To the intermediate samples, in the range 0 x 0:6, is possible that this property is maintained and is also dependent of the doping, but data are not sucient for a statement categor- ically. In temperatures below of TC, we observed that addition of Manganese in system cause signicant changes in the magnetization curve as a function of temperature, which evolves from typical characteristics of magnetism governed by iron for typical samples Manganese-rich. With the results of magnetization we propose a phase diagram, in which indicate the dependency of TC and of the possible TSR as increased of doping. But it is clear that the prospects of work point to the complementation of study of the magnetic and crystallographic property and other physics property which can be explored.

ASSUNTO(S)

reorientacão de spin antiferromagnetismo transicão de fas fisica spin reorientation antiferromagnetism phase transition.

ACESSO AO ARTIGO

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