【摘要】 本文研究了钡-钇-铜氧化物的高Tc超导电性,其名义组份为Ba_xY_1-xCuO_3-y（0.05≤x≤0.95）。结果表明,x<0.50时,超导转变温度TC_1/2随组份x单调上升;在较宽的组份范围0.60<C<0.80内,零电阻温度TcL都高于90K,超导转变宽度△Tc～3K。交流磁化率测量表明,在这个超导系列中,抗磁性几乎与电阻的起始转变同时出现。其TConset～100K。X-射线分析证明了单相样品对应于组份Ba_0.65Y_0.35CuO_3-y更多还原

【Abstract】 We have investigated various compositions of Ba_xY（1-x）CuO_3-y system, resulting in the observation of high and sharp superconducting transitions in ac susceptibility and resistance with a zero-R state above 90 K and R-transition widths about 3 K for a wider composition range 0.50≤x≤0.80. For x below 0.50, the midpoint temperature of resistive transitions is monotone increasing with the composition x. AC susceptibility measurements indicate that all onset x-transition temperatures are close to that of R-transition. X-ray analysis reveal the pure single-phase compound corresponds to a nominal composition Ba_0.65Y_0.35CuO_3-y and the others x=0.50, 0.60, 0.70, 0.75 and 0.80 approximate to single-phase. Compounds with the singlephase structure of oxygen defect-perovskite which may be of an orthorhombic type always exhibite a high.TcL. superconductivity.更多还原