Phase separation in oxygen deficient ΗοBa₂Cu₃O_7-δ single crystals: effect of high pressure and twin boundaries

We investigate the influence of high hydrostatic pressure on the electrical resistance in the ab-plane in HoBa2Cu3O7– δ single crystals with oxygen deficiency. It is determined that the high-pressure-induced redistribution of labile oxygen enhances phase separation, which is accompanied by structural relaxation and ascending diffusion within the volume of the sample. This results in a significant displacement of the temperature intervals that correspond to metal-to-dielectric-type transitions. It is determined that the formation of the low-temperature phase can occur at the twin boundaries.