Vibrating wire magnetic susceptometer

The growing interest in the field of nanoscale magnetic systems, especially regarding thin films and multilayers, emphasizes the need for sensitive measurement techniques. A new type of magnetic susceptometer, based on an alternative field gradient, is described. The mechanical resonating element is a long, thin, metallic wire. A complementary component generates a large local field gradient while keeping the field intensity as low as possible. The basic configuration of a typical instrument is presented and a general theoretical treatment is given concerning the magnetic force, the mechanical sensitivity of the vibrating system, and the vibration sensor.