Nd1+xBa2−xCu3Oy phases have been investigated with x = 0.05, 0.2, 0.4, 0.6 and 0.8. A micro-Raman study has been performed on the entire solid solution range and Nd1.6Ba1.4Cu3Oy composition has been observed by TEM. We have shown two structural transitions since the structure is orthorhombic for x = 0.05, tetragonal for 0.2 < x < 0.6 and orthorhombic for x = 0.8. The solid solution changes the vibration of the lattice significantly. An oxygen ordering is observed at x = 0.6 whereas there is no cation ordering in the structure in Raman spectrometry and TEM analysis. No spinodal decomposition is present in Nd1.6Ba1.4Cu3Oy even if an Ar annealing is performed on the powder. The cation ordering appears at x = 0.8 leading to the structural transition.
Structural investigation of solid solution in Nd1+xBa2-xCu3O7
FERRETTI, MAURIZIO;
2004-01-01
Abstract
Nd1+xBa2−xCu3Oy phases have been investigated with x = 0.05, 0.2, 0.4, 0.6 and 0.8. A micro-Raman study has been performed on the entire solid solution range and Nd1.6Ba1.4Cu3Oy composition has been observed by TEM. We have shown two structural transitions since the structure is orthorhombic for x = 0.05, tetragonal for 0.2 < x < 0.6 and orthorhombic for x = 0.8. The solid solution changes the vibration of the lattice significantly. An oxygen ordering is observed at x = 0.6 whereas there is no cation ordering in the structure in Raman spectrometry and TEM analysis. No spinodal decomposition is present in Nd1.6Ba1.4Cu3Oy even if an Ar annealing is performed on the powder. The cation ordering appears at x = 0.8 leading to the structural transition.
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