Yb-Ba-Cu(O,F )体系超导电性、点阵常数和热学特性的研究

THE SUPERCONDUCTIVITY, LATTICE PARAMETER AND THERMAL CHARACTERISTICS OF THE Yb-Ba-Cu(O, F) SYSTEM

本文叙述了Yb-Ba-Cu(O,F)体系超导体的制备,点阵常数、单胞体积以及T_c随F加入量和O含量的变化。实验结果表明,在YbBa_2Cu_3O_(7-x-δ)F_(2x)(0≤x≤1)体系中,O含量越低,T_c越高,点阵常数和单胞体积就越大。晶体结构分析结果证明点阵常数a与b的差值愈大的正交相结构,其超导性能愈好,表明一维Cu-O链结构对高T_c超导机制有重要作用。

Superconductive samples with compositions of YbBa_2Cu_3F_(2x)O_(7-x-δ) (0 ≤ x≤ 1) have been prepared. The variations of Tc, lattice constants and cell volume with the fluorine dose have been described. We report an experimental observation of an increase of Tc with a decrease of the oxygen content in the YbBa_2Cu_3T?2xO_(7-x-δ) (0 ≤ x≤ 1). Therefore with the content of oxygen increasing, the lattice constants and cell volume of the superconducter become larger. The higher Tc, the larger is the velue of lattice constants (b-a) of the orthorhombic structure. It has been shown that the M-Cu-O or Cu-O part of the systems may have an essential role or the superconductivity.