The Electrical Conductivity of Transition Metals

1-In a recent paper* certain properties of the transition metals Ni, Pd, and Pt and of their alloys with Cu, Ag, and Au have been discussed from the point of view of the electron theory of metals based on quantum mechanics. In particular, a qualitative explanation was given of the relatively high electrical resistance of the transition metals. It was shown from an examination of the experimental evidence that the conduction electrons in these metals have wave functions derived mainly from s states just as in Cu, Ag, and Au, and that the effective number of conduction electrons is not much less than in the noble metals. On the other hand, the mean free path is much smaller, because under the influence of the lattice vibrations the conduction electrons may make transitions to the unoccupied d states, and the probability of these transitions is several times greater than the probability of ordinary scattering. Since the unoccupied d states are responsible for the ferromagnetism or high paramagnetism of the transition elements, there is a direct connexion between the magnetic properties and the electrical conductivity. The purpose of this paper is as follows: in ?? 2, 3, and 4 we develop a formal theory of conductivity for metals, such as the transition metals, where two Brillouin zones are of importance for the conductivity; in ? 5 we apply the theory to show why, at high temperatures, the temperature coefficient of the paramagnetic metals Pd and Pt falls below the normal value; and in ? 6 we discuss the resistance of ferromagnetic metals, and show in ? 7 qualitatively why constantan (Cu-Ni) has zero temperature coefficient at room temperature.