SEARCH FOR SUPERCONDUCTIVITY IN GD2-XCEXSR2CU2TIOY

We report the results of electrical resistivity (rho) measurements on the oxides, Gd2-xCexSr2Cu2TiOy (x = 0.0, 0.05, 0.5 and 1.0), prepared in air, inert and oxygen atmospheres, in the temperature interval 13-3 00 K in order to search for superconductivity, predicted by Blackstead et al. [1]. No superconductivity could be observed in the temperature range of investigation. The interesting feature is that the absolute values of rho however decrease drastically with the initial replacemen t of Gd by Ce though, for higher Ce concentration, the trend is revers ed; the temperature derivative of rho remains negative for all these o xides. It appears that the conduction mechanism is complex in these ox ides. (C) 1998 Elsevier Science Ltd. All rights reserved.