Effect of Oxygen Deficiency on the Compressibility of High-T_c Superconductor YBa₂Cu₃O_7−δ

Abstract

The effect of pressure on the lattice constant and crystal structure of YBa₂Cu₃O_7−δ (YBCO) has been studied up to about 120 kbar at room temperature in the wide range of δ, 0<δ<1. It is found that the lattice compression of all samples is anisotropic, and the volume compressibility of superconducting YBCO increases with δ, having a peak near the orthorhombic-tetragonal phase boundary δ\simeq0.8.