Induced torque of sodium measured by a modulation method

The induced torque in sodium detected by a new modulation method is anisotropic with twofold anisotropy at low fields. Fourfold torque does not develop in magnetic fields up to 2 T as is observed in potassium. The results are not explained completely by the theory of Lass assuming ellipsoidal boundary conditions or by the theory of Bishop and Overhauser for the charge density wave model.