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 u sing standard lithographic techniques from a single-crystal silicon wa fer. 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 m otion is detected through a capacitance measurement. The small torsion constant of the oscillator combined with a Q value > 10(6) allow dete ction of magnetic moments as small as 10(-13) A m(2). Magnetometer sen sitivity is measured using small superconducting open cylinders machin ed from aluminum. (C) 1998 American Institute of Physics. [S0034-6748( 98)03710-1].