Variation of the pressure dependence of the superconducting transition temperature with x in La_1−xSr_x CuO₄

Hydrostatic pressure measurements of the superconducting transition temperature were made as a function of x in La_2−xSr_x CuO₄. A sharp change in the behavior occurs between x = 0.2 and 0.25 in that the pressure derivative goes from positive to essentially zero. This result is discussed in the context of band structure models.