Pressure-induced charge transfer and hole depletion in (Nd1-xPrx)Ba2Cu3O7

We have systematically studied the pressure (P) effects on the normal state resistivity and on the superconducting transition temperature T-c for the series of (Nd1-xPrx)Ba2Cu3O7. Our results show that the functions T-c(x) an d dT(c)/dP(x) are not directly related to each other, suggesting that the f actor controlling the x-dependent T-c in (Nd1-xPrx)Ba2Cu3O7 is not sensitiv e to pressure. However, we have found that the x dependency of dT(c)/dP is strongly correlated to the x dependency of the pressure effect on carrier c oncentration. We therefore attribute the origin of pressure-induced T-c var iation in (Nd1-xPrx)Ba2Cu3O7 to a combined effect of pressure induced charg e transfer and pressure-induced hole depletion. (C) 2000 Elsevier Science B .V. All rights reserved.