ON THE POSSIBLE MECHANISM OF THE SUCCESSIVE STRUCTURAL TRANSITIONS OF LA2-XBAXCUO4 - STUDY BY THE LI SUBSTITUTION FOR CU

Transport and magnetic properties of La2-xBaxCu1-yLiyO4 have been studied with varying both the hole concentration and the ration of Ba to La, independently. The depression of the superconducting transition temperature is always found around a fixed hole concentration for the series of samples with different values of Ba/La. This fact suggests that the atomic ordering of La and Ba is not primarily important, even if it exists, for the realization of the low temperature tetragonal phase. A brief comment which excludes the possibility that only in the narrow range of x around 0.15 the superconductivity appears, is also given. © 1990.