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Crystal Structure and Superconductivity Controlled by Cation Substitution and Oxygen Annealing in Y 1-x Ca x Ba 2 Cu 3 O y and YBa 2-x La x Cu 3 O y

1988; Institute of Physics; Volume: 27; Issue: 6A Linguagem: Inglês

10.1143/jjap.27.l1009

1347-4065

Ayako Tokiwa, Yasuhiko Syono, Masae Kikuchi, Reiko Suzuki, Tsuyoshi Kajitani, Norio Kobayashi, Takako Sasaki, Osamu Nakatsu, Yoshio Mutô,

Magnetic properties of thin films

The effects of Ca 2+ substitution for Y 3+ and La 3+ substitution for Ba 2+ in YBa 2 Cu 3 O 7 on the structural and superconducting properties were studied to control the average copper charge. Single-phase tripled perovskites were obtained for 0≦ x ≦0.2 and 0≦ x ≦1.0 for Ca and La doped series, respectively. A slight decrease of T c with increasing x was found for small x values for both kinds of substituted specimens prepared by furnace cooling in air. Oxygen annealing experiments were also carried out. These suggested that the superconduction in the Y-Ba-Cu-O system cannot be interpreted only by oxygen content or average copper charge.