High-Q oscillator torque magnetometer

We describe a torque magnetometer for use at low temperatures based on a high-Q silicon torsional oscillator. The oscillator is fabricated using standard lithographic techniques from a single-crystal silicon wafer. The sample stage of the oscillator has an area of 0.57 cm(2) and is suitable for deposition of thin magnetic film samples. Oscillator motion is detected through a capacitance measurement. The small torsion constant of the oscillator combined with a Q value > 10(6) allow detection of magnetic moments as small as 10(-13) A m(2). Magnetometer sensitivity is measured using small superconducting open cylinders machined from aluminum. (C) 1998 American Institute of Physics. [S0034-6748(98)03710-1].