A galvanomagnetic effect is described which is observed by measuring the induced voltage normal to the direction of current flow as in the Hall effect but with the magnetic field in the current-voltage plane. The measurements enable us to test the assumptions of spherical energy surfaces and spherical relaxation time surfaces for semiconductors. If these assumptions are correct, the effect should be isotropic. Preliminary room temperature measurements show this effect to be anisotropic in both $p$- and $n$-type germanium, in agreement with magnetoresistance measurements.

• Received 5 February 1954

DOI:https://doi.org/10.1103/PhysRev.94.1121