Surface reflection and nonlinearities in ac Hall measurements of liquid metals

It has been confirmed that nonlinearities at the electrode interface cause spurious signals similar to Hall signals when the two-frequency ac method is applied to Hall measurement of liquid state materials. From the analysis of the results of surface reflection of a laser beam, Hall coefficients for liquid mercury and gallium have been obtained in the higher frequency region using our recently developed ac-dc method. It has also been found that other spurious signals result from the electric resistance change caused by sample movements and intrinsic magnetoresistance due to a Lorentz force. The resistance change in the higher frequency region is proportional to B and B2 in the liquid states, however no change is observed in the solid state.