Pressure Dependence of the Tetragonal-Orthorhombic Transition in La1.88 Sr0.12 Cu O4-δ: A Single Crystal X-Ray Study

ABSTRACTWe report the first combined high pressure (up to 30 kbar) and low temperature (10 K - 300 K) single crystal X-ray diffraction study of the tetra-gonal-orthorhombic transition in La2−xCuO4-δ(x=0.12). Superstructure reflections of the orthorhombic phase were used to characterize the transition. The transition temperature, TT–O, is found to decrease under pressure and the orthorhombic phase is suppressed above about 15 kbar. These results confirm that both phases are superconducting and suggest to attribute a previously reported kink in dTc/dP to different rates of increase of Tc for the tetragonal and orthorhombic phases.