Microcantilever torque magnetometry is used to measure quantitative M-H curves on patterned Ni80Fe20 films. The dynamic deflection method is employed, in which a small film is deposited onto a microcantilever and placed in an external magnetic field. A small orthogonal ac torque field is applied at the cantilever resonant frequency, and the resulting torque is measure as a function of external field. Cantilever fabrication has been integrated with film deposition. Results are presented for a 5 micron x 5 micron x 30 nm NiFe film. The measured saturated magnetic moment of the sample si 5.1 × 10-13 ± 2 × 10-14 Am2 for a 100 A/m torque filed. The M-H curves for the smaller films show hysteretic switching consistent with a series of stable multi-domain states. Values of the saturation magnetization are within 3% of the value measured on similar samples by ferromagnetic resonance, indicating this is a sensitive method for measuring magnetic reversal in small ferromagnetic samples.
Citation: Journal of Applied Physics
Pub Type: Journals
cantilever magnetometry, micromechanical systems, patterned films