Abstract
The results on structural aspects and superconductivity of LaBaCaCu 3O 7+ δ (La:1113) are reported. Both X-ray and neutron diffraction studies have been carried out on this compound which reveal that this compound crystallizes in the tetragonal structure (space group P4/ mmm). Detailed analysis of the neutron diffraction data reveals that the Ca, Ba and La atoms in this compound are intermixed at the nominal La and Ba sites. Nearly 46% of Ca occupy the usual La-site, while the remaining 54% occupies the Ba-site. Consequently, a corresponding amount of La substitutes at the Ba-site. The intermixing of Ca, Ba and La sites randomizes the chain site oxygens leading to a tetragonal structure for this compound despite an oxygen content close to 7. These occupancy refinements explain the tetragonal structure of the compound, despite having an oxygen content close to 7.04. The compound studied presently shows a sharp superconducting transition at about 68 K.
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