ELECTRICAL-RESISTIVITY OF CO-NI-PD AND CO-PD ALLOYS

Three series of ferromagnetic alloys have been made: Co100-xPdx, Co25Ni75-yPdy and Co5-zNizPd95. The electrical resistivity rho of these alloys was measured from 4 to 300 K. Their high field (H > 2 T) susceptibility CHI-HF was obtained with superconducting quantum interference device measurements at 5 K. Comparing the residual resistivity rho-0 of Co-Ni and Co-Pd, it is found that the spin-up resistivity rho-up of Co-Ni follows the Nordheim's rule, while that of Co-Pd peaks at x = 85. This indicates the spin-up d band of Co-Pd is not full for all the x values. Also, CHI-HF data reveal the same tendency of the spin-up band. Based on the deviation from Matthiessen's rule of the two-current model, we estimate alpha = rho-0 down/rho-0 up congruent-to 2 for the dilute PdCO alloy, where rho-0 = rho down rho-0 up/(rho-0 up + rho-0 down), from the residual resistivity of the ternary Co5-zNizPd95 alloy and from the temperature dependence of rho(T) of the binary Co5Pd95 alloy