PHASE CONVERSION IN LA2CUO4 SUPERCONDUCTORS

被引：5

作者：

PARK, JC ^{[1
]}

HUONG, PV ^{[1
]}

GRENIER, JC ^{[1
]}

WATTIAUX, A ^{[1
]}

机构：

[1] UNIV BORDEAUX 1,CNRS,URA 124,SPECTROSCOPIE MOLEC & CRISTALLINE,F-33405 TALENCE,FRANCE

来源：

JOURNAL OF THE LESS-COMMON METALS | 1990年 / 164卷

关键词：

D O I：

10.1016/0022-5088(90)90494-5

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

La2CuO4 ceramics prepared by different methods, in particular by electrochemical oxidation and single crystals undoped and doped with Sr or Ba, were studied at various temperatures by laser local heating. Evidence of two orthorhombic isophases in reversible equilibrium was shown and characterized by Raman spectroscopy. The high temperature isophase is rich in oxygen. The enthalpy of the phases conversion has been evaluated to 1.5 kilocal.mole-1. The sample obtained by electrochemical oxidation which gives the superconductivity at Tc = 42 K, is identified as having an orthorhombic structure with higher distortion than in stoichiometric La2CuO4. The Raman characteristics are also given for the tetragonal structure, in particular for La1.85Sr0.15CuO4 and La1.85Ba0.15 CuO4. © 1990.

引用

页码：862 / 869

页数：8