Phase equilibria in La(Y)-Ba-Cu-O systems and growth of high-T/sub c/ superconductor bulk single crystals

The isobaric phase diagrams of BaO(La/sub 2/O/sub 3/)-CuO-CuO/sub 0.5/ systems at a partial oxygen pressure of 0.021 MPa and the phase transition BaO/sub 2/ to or from BaO at oxygen pressure up to 2.1 MPa were studied. A flux method for growing bulk single crystals of YBa/sub 2/Cu/sub 3/O/sub 7- delta /, La/sub 2/CuO/sub 4/, (LaSr)/sub 2/CuO/sub 4/, Nd/sub 2/CuO/sub 4/, and (NdCe)/sub 2/CuO/sub 4/ has been developed using a rotatable crucible which ensures separation of crystals from the melt. The effects of temperature, oxygen pressure, and heat-treatment duration on the superconducting characteristics of the crystals were studied.