2001 年 11 巻 1 号 p. 12-20
For RBa2Cu3Oy(R=Ln and Y), the relationship between superconducting transition temperature Tc, overdoping oxygen content Δy, and R was obtained through studies of oxidation under pressure. Tc of RBa2Cu3Oy remains almost unchanged through various levels of overdoping for small inonic radii of R. As the ionic radius of R increases, Tc decreases with the level of overdoping. The decrease changes systematically from Eu to La; the decrease for La is the steepest. This general view is somewhat modified by the temperature of overdoping. Overdoped oxygen seems to settle down on CuO and/or the Y plane depending also on the treating temperature.