An investigation was made of  the influence of high hydrostatic pressure on the electrical resistance in the ab-plane in HoBa2Cu3O7-δ single crystals with oxygen deficiency. It was determined that the high-pressure-induced redistribution of labile oxygen enhances phase separation, which was 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 was determined that the formation of the low-temperature phase can occur at the twin boundaries.

Phase Separation in Oxygen Deficient ΗοBa2Cu3O7-δ Single Crystals: Effect of High Pressure and Twin Boundaries. R.V.Vovk, Z.F.Nazyrov, M.A.Obolenskii, I.L.Goulatis, A.Chroneos, V.M.Pinto Simoes: Philosophical Magazine, 2011, 91[17], 2291-302