BANDWIDTH-DEPENDENT AND DOPING-DEPENDENT PRESSURE EFFECTS ON THE FERROMAGNETIC TRANSITION IN PEROVSKITE MANGANITES

Effects of hydrostatic pressure on the magnetic and transport properti es of R(1-x)Sr(x)MnO(3) have been investigated with systematic variati on 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 less than or equal to 0.4). The coefficients at x approximate to 1/2, however, are found to deviate from the above relation due to competing antiferromagnetic and/or charge-ordering interaction.