SUPERCONDUCTING TRANSITIONS OF THE (YB,LU,SC)BA2CU3O7-Y SYSTEMS

[[abstract]]In the rare earth barium copper oxide system RBa2Cu3O7-y, almost all compounds show superconductivity above 90 K (R = Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Th) (1–10). However, no YBa2Cu3O7-type phase or superconductivity was observed in ScBa2Cu3O7 (11,12). Whether this is due to smaller ionic radius of the Sc3+ ion (0.73 Å) or difficult sample preparation condition is not clear. In order to check these possibilities, we study two pseudoquaternary systems (Yb1−xScx) Ba2Cu3O7−y and (Lu1−xScx)Ba2Cu3O7−y where ionic radii of Yb3+ (0.86 Å) and Lu3+ (0.85 A) are closer to Sc3+ ion. Superconducting properties of these two systems from electrical and magnetic measurements as well as crystallographic properties will be discussed in detail.[[fileno]]2010141010017[[department]]物理