Hall Effect of Gadolinium, Lutetium, and Yttrium Single Crystals

Hall-effect measurements have been made on single crystals of gadolinium (hcp) in magnetic fields up to 30 kOe applied along the [$11\overline{2}0$] ($a$ axis), [$10\overline{1}0$] ($b$ axis), and [0001] ($c$ axis) directions. The temperature range covered was 4.2-340°K. Large anisotropy and strong temperature dependence were observed for both $R_0$, the ordinary Hall coefficient, and $R_1$, the extraordinary Hall coefficient. These results are interpreted in terms of Fermi-surface anisotropy and exchange splitting of the conduction band. Hall-effect measurements have been made on single crystals of lutetium (hcp) and yttrium (hcp) in magnetic fields up to 7.8 kOe applied along the $a$, $b$, and $c$ axes. The temperature range covered was 8-320°K. The Hall coefficients of these metals showed large anisotropy and strong temperature dependence. The anisotropy is interpreted in terms of Fermi-surface anisotropy and the temperature dependence is explained in terms of a transition from impurity scattering at low temperatures to scattering from phonons at high temperatures.