Flux growth of single crystals of NdyPr1-yGaO3 solid solutions as substrates for high temperature superconductor films

Single crystals of solid solutions between NdGaO3 and PrGaO3 have been obtained from a PbO-PbF2-MoO3 flux. The flux method grew single crystals up to 4.5 x 4 x 2 mm (from 20 cm3 crucible) in the temperature range 1280-1080°C. The aim was to avoid the cubic-to-orthorhombic phase transition, usually causing twinning in rare earth gallates. The chemical composition, its dependence on crystal growth conditions and the impurity levels have been established by EPMA and by EDAX analysis. Strong influence of chemical composition on the crystal quality has been observed. High resolution Guinier camera powder patterns have been used to determine lattice parameters of obtained single crystals. Because the lattice parameters, depending on composition, are in the range a = 5.42-5.45 Å, b = 5.48-5.52 Å, c = 7.70-7.74 Å, such solid solutions can be regarded as potential materials for substrates for thin films of YBa2Cu3Ox, Pb2Sr2(Y,Ca)Cu3Ox, and related Bi-based and Tl-based superconductors.