A vibrating sample magnetometer for use with a superconducting magnet

A simply constructed vibrating sample magnetometer is described which may conveniently be used with the sample in the bore of a superconducting solenoid. The magnetometer measures the total magnetic moment of a sample which is vibrating parallel to a uniform applied magnetizing field, and a sensitivity (defined as the smallest detectable change of magnetic moment) of 0.5 nA m 2 (0.5 mu emu) has been achieved. Automatic balancing of the magnetometer is used so that measurements are insensitive to possible circuit nonlinearities and drift, and to changes in the vibration amplitude, frequency and circuit gain.