High resolution neutron diffraction study of La1-xSrxCoO3

초록

Recently interests in strontium-doped lanthanum-cobalt oxides, La1-xSrxCoO3 (LSCO), have been motivated by their advanced high electrical and excellent ionic conductivity properties. These features make them good candidate materials for electrodes in fuel cells and ferroelectric memory devices where their practical applications were hindered by technical difficulties such as fatigue and imprint. Polycrystalline La1-xSrxCoO3 (x=0.15, 0.25) bulk samples were prepared by the standard solid-state reaction. The structural property of the samples was characterized by the X-ray diffraction and by the X-ray photoemission spectroscopy. By measuring the temperature dependence of inverse magnetic susceptibility, the Curie temperatures are determined to be 147, 217 and 232K for x = 0.15 and 0.25 samples, respectively. The zero-field cooled magnetization measurements revealed a spin-glass like behavior for x=0.15. Interestingly, the neutron diffraction data demonstrated no evidence of antoferromagnetic phase at low temperatures. Our data reflect that more advanced magnetic model is required to elucidate the spin-glass behavior at low Sr concentrations.