Bandwidth- and Doping-Dependent Pressure Effects on the Ferromagnetic Transition in Perovskite Manganites

Abstract

Effects of hydrostatic pressure on the magnetic and transport properties of R_1-xSr_xMnO₃ have been investigated with systematic variation of the one-electron bandwidth (W) of a conduction electron, as well as of the doping level (x).The positive pressure coefficient (dlnT_C/dP) of the Curie temperature is observed for all the compounds, and its absolute value increases with decrease of W, or equivalently, T_C.We have derived a nearly x-independent empirical relation between the coefficient and T_C in the lightly doped region (x≤ 0.4).The coefficients at x≈1/2, however, are found to deviate from the above relation due to competing antiferromagnetic and/or charge-ordering interaction.