GROWTH OF THE SUBSTRATE CRYSTALS FOR $La_{2-x}Sr_xCuO_4$ THICK FILMS

Single crystal of Li2Cu1-xMxO4 (M=Ni, Zn) are promising as a substrate to realize superconducting electronic devices. The distribution coefficients of Ni and Zn to the Cu site in La2CuO4 (LCO) were estimated by the zone melting technique to grow high quality single crystals of La2Cu1-xMxO4(M=Ni, Zn). The distribution coefficient value of Ni was estimated to be 4.2 and that of Zn was estimated to be 0.66, respectively. Suitable solvent compositions were determined using these values to grow single crystals by he traveling floating zone (TSFZ) method. Single crystal of LCO, La2Cu1-xMxO4(M=Ni(x=0.01, 0.02, 0.03, 0.04), Zn(x=0.01, 0.02, 0.03) of high homogeneity were grown. The behaviors of the magnetization of these as-grown crystals do not indicate superconductivity except LCO. Ni or Zn substitution can make LCO non superconductor. This fact suggest that single crystals substituted by Ni or Zn are useful as substrate crystals.