Low Temperature Resistivity of the Transition Elements: Ruthenium and Osmium

Experimental values are reported for the electrical resistivity of ruthenium and osmium from 2 to 300 °K and for the thermal resistivity from 2 to 140° K. The samples were produced by arc-melting pressed pellets of metallic powder in an inert gas atmosphere. Two osmium samples and one ruthenium sample showed a satisfactorily low residual electrical resistance. By grinding these rods to a regular shape, absolute values of resistivity were obtained and the impurity and thermal components of resistivity derived; at room temperature (295 °K) we deduce that for ideally pure Os, [Formula: see text] and for ideally pure ruthenium [Formula: see text]. The temperature dependence of the resistivity was markedly different for another ruthenium sample but it seems likely that this was not representative of pure h.c.p. ruthenium.