High-Pressure X-Ray Study on (L1-xAx)aCubOcSystem

Abstract

The (L_1-xA_x)_aCu_bO_c system have high T_c superconductivity, where L stands for La, Y and so on, A for the alkaline earth elements, like Ba, Sr and so on. The pressure effect on the lattice constants of YBa₂Cu₃O_7-y has been measured at room temperature up to 60 kbar. Compression coefficients of a- and c-axis are found to be almost the same value of (3.3±0.3)×10^-4 kbar^-1, which is larger than the value for (La_0.9Sr_0.1)₂CuO₄ and the ratio of c/a is found to be almost constant, whose tendency was observed in (La_0.9Sr_0.1)₂CuO₄. But the ratio of a/b decreases slightly under pressure.