Nanotorsional resonator torque magnetometry

Magnetic torque is used to actuate nanotorsional resonators, which are fabricated by focused-ion-beam milling of permalloy coated silicon nitride membranes. Optical interferometry is used to measure the mechanical response of two torsion modes at resonance, which is proportional to the magnetization vector of the nanomagnetic volume. By varying the bias magnetic field, the magnetic behavior can be measured with excellent sensitivity ( ≈ 10 8 μ B ) for single magnetic elements.