Residual electrical resistivity of high-purity metals

We have selected the lowest values of δ0 = ρ0/ρ293 from the known literature for all metals except the rare earths. We find that 20 metals can be considered as being of high purity in terms of the value of δ0, while the following 16 metals are the dirtiest: Rb, Ca, Sr, Ba, Hf, As, Mn, Cr, Co, Sc, Y, Tc, Th, U, Pu, Np. It is shown that the high-purity values of δ4.2 for Hg, Ga, In, Cs, and Tl are not characteristic of their “electronic” purity; it is necessary to make the measurements at still lower temperatures (0.5–1.5 K). We compute the value of the ideal resistance δ (4.2) for 28 metals at T = 4.2 K and estimate the magnitude of the residual temperature. We establish the relationship between δ(4.2) and ΘD and the electronic specific heat for both transition and nontransition metals. We also find a precise value for δ0 for high-purity Pb.

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