Abstract
We report detailed studies of the normal-state resistivity and Hall effect in bulk R 0.9 Ca 0.1 Ba 2 Cu 3 O 7-δ systems (R=Tm, Ho, Gd, and Nd). We find a linear temperature dependence of the normal-state resistivity ρ n (ρ n αT) and the Hall number n H (n H αT) above T c . For a fixed temperature both ρ n and n H are dependent on the ionic radius of the rare earth r R 3+ ; viz., the larger the R 3+ ionic radius, the larger ρ n (ρ n αr R 3+ ), but the lower n H (n H α1/ rR 3+ ). At a constant temperature the p n α1/n H relation is well confirmed for R 0.9 Ca 0.1 Ba 2 Cu 3 O 7-δ compounds with different R ions. The cotangent of the Hall angle follows a universal T 2 dependence i.e., cot θ H =αT 2 +C. The slope a decreases with increasing ion size of the rare earth, but the quantity C remains almost constant for R 0.9 Ca 0.1 Ba 2 Cu 3 O 7-δ compounds with different R. The reduction of T c and the R 3+ ion-size dependence of ρ n and n H is interpreted in terms of hole generation and hole localization by Ca doping.