【摘要】 用溶液共沉淀法（湿法）制备了Y_0.6Ba_0.8CuO_x超导体,其中点转变温度为94.1K,转变宽度为1.2K,对样品在二周时间内进行20次从液氮温度到室温、从液氮环境到空气环境的冷热循环,发现在1—3次冷热循环后,超导转变温度略有下降,然后稳定在91.5K左右。在正常态（室温）及超导态（77K）进行X射线分析,表明样品为两相的多晶体,有超导性的主相为正交缺氧的钙钛矿超结构。正常态与超导态的晶格结构没有变化。更多还原

【Abstract】 Stable and reproducable high-Tc superconductors with nominal composition Y0.6Ba0.8CuO₂ have been prepared by a coprecipitation method from acqueous solutions. The resistive transition starts from 95.1 K, and is completed at 92.6 K, with a mid-point transition temperature Tcm= 94.1 K, and a transition width △T=1.2K. A sample has been treated with 20 cycles from liquid-nitrogen temperature to room temperature and from liquid nitrogen to atmospheric ambiences. After 1-3 thermal cycles, the superconducting temperature has dropped a little, then stablized at about 91.5 K. Crystal structure of the sample both in normal state （at room temperature） and in superconducting state （at 77K） has been determined by X-ray diffraction. Analysis shows this compound is a double-phase polycrystal, whose main phase is an orthor-hombic, oxygen-dificient perovskite superstructure. No structural difference has been found between the normal state and the superconducting state, except for a little reduction of the lattice constants （for normal state,a=3.806 A,b=3.947 A,c=11.862A; for superconducting state, a =3.768 A,b=3.922 A,c=11.829 A）.更多还原