Hall Coefficients of Liquid Metals

The Hall coefficients $R$ of 9 liquid metals were accurately measured using an alternating-current-alternating-magnetic-field method. Four of these metals have $R=R_0\equiv \frac{1}{\mathrm{nec}}$, which is the value predicted by the free-electron model of liquid metals. The Hall coefficients of these metals (in units of ${10}^{-5\mathrm{}}$ ${\mathrm{cm}}^3$/C) are Hg, -7.6; Cd, -7.2; Zn, -5.2; and Sn, -4.4. The other five metals were found to have $\frac{R}{R_0}<1\mathrm{}$, with Ga, -3.83; In, -5.3; Tl, -4.8; Pb, -3.7; and Bi, -3.0. The absolute experimental error for Ga is ±2.5%. The experimental error for all other metals relative to Ga is approximately ±1.5% except for Pb (±12%). The free-electron model of liquid metals is discussed. The value of $\frac{R}{R_0}$ is compared with the magnitude of the mean free path. Comparison is also made with the Hall coefficients of other allotropic forms of these metals.