High Tc Superconductor, YBa2 Cu3 O7-<TEX>$delta$</TEX>; (I) Its Preparation and Physicochemical Characterization

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J. Korean Ceram. Soc. > Volume 25(2); 1988 > Article

Journal of the Korean Ceramic Society 1988;25(2): 154.

고온 초전도체 YBa2 Cu3 O7-$delta$;(1) 합성 및 물리화학적 특성 연구

최진호, 변송호, 홍승태, 정덕영, 최석용, 김배환, 김진태, 노동윤, 유한일¹

서울대학교 화학과
¹서울대학교 무기재료공학과

High Tc Superconductor, YBa2 Cu3 O7-$delta$; (I) Its Preparation and Physicochemical Characterization

ABSTRACT

Almost single phase of Y1Ba2Cu3Ox, which exhibits the onset of superconducting transition at 90K, has been prepared via a conventional ceramic processing route followed by an anneal for a period of 10 hours at 45$0^{circ}C$ in an atmosphere of 100% O2. The mean value for the oxygen content has been determined as x=6.85$pm$0.02 by an iodometric titration technique. X-ray photoemission spectra are found to be consistent with a mixture of the d8(Cu3+) and d9(Cu2+) as the ground state and reveals that the local concentration of Cu3+ decreases with depth from the surface where x corresponds to 7.0. This is explained as being associated with the intercalation of oxygen during cooling from the annealing temperature.