Magnetoresistance of gallium

The magnetoresistance of gallium has been studied for b-axis current direction in fields up to 20 k0e. "Rotation curves" of magnetoresistance versus magnetic field direction exhibited both principal and subsidiary minima. These minima are discussed using the pseudopotential model of the Fermi surface and major topological dimensions of the sixth-band hole surface are measured using observed angular ranges of subsidiary minima. The principal minima result from the ka and kc open trajectories. The subsidiary minima are shown to occur by means of nonsaturating ka open trajectories, extended orbits, and [Formula: see text] effects involving local variations in both effective mass and relaxation time parameters. The temperature dependence of the magnetoresistance was measured for field directions in the ac plane. Relaxation time ratios derived through Kohler's rule are anisotropically scaled with temperature, indicating deviations from Kohler's rule.