CRYSTAL-GROWTH OF (LA,SR)(2)CUO4 BY FLOAT-ZONE MELTING

High quality single crystals of La2-xSrxCuO4 (x=0.15, 0.20) have been successfully grown using the floating zone method. Stoichiometric feed rods were prepared with a density high enough to directly zone refine , The chemical composition of the molten zone was allowed to establish itself during the first few zone lengths, thus no nonstoichiometric s eed rod was necessary, Neutron diffraction shows the boule is composed of several large grains. The grain boundaries are found to be Sr-rich , containing La2SrCu2O6. Electron microscopy, X-ray back-reflection La ue and AC susceptibility data are used to characterize the crystals.