Interpretation of Knight Shifts and Susceptibilities of Transition Metals: Platinum

Abstract

Measurements of the magnitude, sign, and temperature dependence of the Knight shift and susceptibility in platinum are used to determine the contributions to each arising from the spin paramagnetism of the $s$ and $d$ bands, the orbital paramagnetism and the core diamagnetism. A complete expression for the orbital contribution to the Knight shift in a transition metal is derived, including spin-orbit coupling. We show that in the tight-binding limit, as in the free ion, a simple relation exists between the orbital susceptibility and the orbital hyperfine field. The relation of the enhancement of the $d$-spin susceptibility over its specific heat value to the possible occurrence of superconductivity is discussed.