U（Th）—Y—Ba—Cu—O体系的超导电性研究

Superconductivity in the U(Th)-Y-Ba-Cu-O systems

High Tc superconductivity has been observed both resistively and magnetically in the new U(Th)-Y-Ba-Cu-O systems. The zero resistance temperature of the three samples with nominal composition of U0.1Y1.1Ba0.8 Cu O4-z, U0.15Y1.05 Ba0.8 Cu4-z and Th0.3Y0.8 Ba0.8 Cu4-z is 87K, 79K and 74K, respectively. The result of ac magnetic susceptibility measurement implies that the superconducting state is realized in the U-doped samples below 90K. The stoichiometry of the U-Y-Ba-Cu-O superconductors has theaid of Rutherford backscattering and nuclear reaction 16O(d, p)17O. The analytical results show that the "real composition" of samples may be different from that of thenominal composition. The X ray diffraction analysis of the U-Y-Ba-Cu-O system showsthat, none of the peaks can be fitted to the uranium oxides and the other raw materiale structure, and its pattern may be attributed to new multiple phases with structure different from the known singlephase superconducting oxides.