【摘要】 用 X 射线衍射法仔细观察了高 T_c 超导材料 YB₂Cu₃O_7-x中四方与正交相的结构转变过程,认为此类结构转变属二级或近似二级相变。它与样品经不同温度退火后的氧含量密切有关,表现在其 X 射线衍射轮廓上的某些细微变化可用来判别其氧含量的范围,以及其吸,放氧过程;如将氧的有序化或作为一种序参量来讨论该材料的超导电性能将是非常有用的。更多还原

【Abstract】 The phase transformation of orthorhombic to tetragonal phase ofY-Ba-Cu-O has been investigated in details by X-ray diffraction.This transformation isof the second order or close to second order has been observed and strongly deponds on theoxygen index which changes with annealing temperature.From some X-ray diffractionline-profile measurements have been presented and shown to be useful for identification ofY-Ba-Cu-O and estimation of oxygen index x in details.The effects of oxygen deficiencyand its ordering on the superconductivity also have been investigated.更多还原