Pressure Dependence of the Knight Shift in Pt

The Knight shift K of Pt¹⁹⁵ in platinum metal was measured as a function of hydrostatic pressure up to about 8000 kg/cm², at three temperatures, 64.8^∘{}, 0^∘{}, and -78.0^∘{}C. $|K|$ decreases with increasing pressure. The pressure dependence of K changes markedly with temperature, following a T² law. The temperature dependence of K at constant volume, which has been derived from the previously obtained $K(T)$ at constant pressure and the present pressure-dependence data, may be written as K=K₀+BT²+O[(TTd)⁴], where Td is the degeneracy temperature of the d-band holes. These observations agree with the model proposed by Clogston et al. The experimental volume dependence of K₀ and B is analyzed using a standard band model. The volume dependences of (i) the Fermi depths of the s and the d band, (ii) the exchange parameter for the d band, and (iii) the number of the d holes are derived from the experimental data.