Concentration and Temperature Dependence of the Electrical Resistivity of Quenched PdH sub x

The hydrogen concentration dependence of the electrical resistivity rho (x) of rapidly cooled PdH sub x samples is investigated at 4.2 and 77.4K for 0 < = x < = 0.015. The resistivity data show that the hydrogen atoms are homogeneously distributed in the host metal up to a concentration x approx = 0.005. In this regime d rho /dx = 25 mu Omega cm. This value is reproduced by a simple model where scattering between electron states on the Gamma sheet on the Fermi surface and between states on the Gamma sheet and the d band jungle-gym is taken into account. This model leads to a maximum in rho (x) at x = 0.4 for temperatures above the critical temperature T sub c = 566K of the PdH sub x system. Below T sub c (especially at 4.2K) the concentration dependence of rho is dominated by the segregation in the alpha and alpha ' phases for O < = x < = 0.65. In this concentration range the experimental data can be described by assuming a random distribution of dilute alpha phase spheres in the alpha ' phase PdH sub x matrix. 25 ref.--AA