Concentration and temperature dependence of the electrical resistivity of quenched PdHx

The hydrogen concentration dependence of the electrical resistivity rho (x) of rapidly cooled PdHx samples is investigated at 4.2K and 77.4K for 0<or=x<or=0.015. The resistivity data show that the hydrogen atoms are homogeneously distributed in the host metal up to a concentration x approximately=0.005. In this regime drho /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 Tc=566K of the PdHx system. Below Tc (especially at 4.2K) the concentration dependence of rho is dominated by the segregation in the alpha and alpha ' phases for 0<or=x<or=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 PdHx matrix.