An AGFM is a highly sensitive measurement system, capable of measuring hysteresis properties on a wide range of sample types and strengths. It uses a modified technique to conventional vibrating sample magnetometry. Traditionally, a sample placed in a magnetic field is vibrated at a fixed frequency via an electro-mechanical transducer[3.2]. In an AGFM, however, an alternating gradient field is utilized to exert a periodic force on a sample placed within a variable or static DC field. The force is proportional to the magnitude of the gradient field and the magnetic moment of the sample. The force deflects the sample and this deflection is measured by a piezoelectric sensing element mounted on the probe arm. The output signal from the piezoelectric element is synchronously detected at the operating frequency of the gradient field. Operating near the mechanical resonant frequency of the assembly enhances the signal from the piezoelectric element. The AGFM in use at ISML, 2900 MicroMag, utilizes a software function that automatically determines the mechanical resonance and sets the appropriate operating frequency for the sample under study and the electromagnet can provide fields up to 20 kOe.