Neytron diffraction study of anisotropy of crystal lattice compression in high-Tc superconductors under pressure

Abstract

Pressure-induced structural changes in irradiated YBa₂Cu₃Ox (л = 6.95) and unirradiated (x = 6.91, 6.54, 6.39) samples have been measured by neutron powder diffraction under high pressure. Tc has been measured for irradiated superconductors under pressure and the value of dTc/dP is found to be high (1.5 K/kbar). The increase in Tc is associated with charge transfer between the CuO₂ planes and CuO chains which is reflected by anisotropy of crystal lattice compression.