Vector vibrating-sample magnetometer with permanent magnet flux source

Abstract

A compact magnetometer, which uses two nested 1?T Halbach cylinders to generate a variable magnetic field of up to 2?T in any direction in the xy plane, has two sets of quadrupole pickup coils to detect the components mx and my of the magnetic moment of a sample vibrating along Oz. Sensitivity is 1.10?7?A?m2 with integration time of 100?ms. The instrument is used to measure longitudinal and transverse hysteresis loops and torque curves, under automatic software control. Three examples illustrating its versatility and sensitivity are provided: CrO2 magnetic recording tape, a cobalt nanowire array in a porous membrane, and a FePt thin film.