Antonio, D., M. I. Dolz, and H. Pastoriza. "Micromechanical magnetometer using an allsilicon nonlinear torsional resonator." Applied Physics Letters 95, no. 13 (2009): 133505–3.
Abstract: In this work, a micromagnetometer employing a nonlinear torsional resonator with a high quality factor Q is presented experimentally. Oscillatory rotation of a conducting plate in the sensed magnetic field H induces eddy currents that dissipate energy. Due to the nonlinear response of the oscillator, the resulting mechanical damping originates frequency shifts in the resonance curve that depend on H. Nonlinearity results from the electrostatic detection, which introduces high order electrical spring constants. The device is fabricated with a standard silicon process and does not incorporate ferromagnetic materials. An analytical nonlinear model that correctly describes the device is also introduced.

Antonio, D., M. I. Dolz, and H. Pastoriza. "Magnetization measurement of single La0.67Ca0.33MnO3 nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator." Journal of Magnetism and Magnetic Materials 322, no. 5 (2010): 488–493.
Abstract: Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La0.67Ca0.33MnO3. The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant kM of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H[not double greaterthan sign]2K/M the magnetization is almost parallel to the applied magnetic field and for H[double lessthan sign]2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition

Libbrecht, S., E. Osquiguil, and Y. Bruynseraede. "Influence of field inhomogeneity on the magnetization of YBCO films." Physica C: Superconductivity and its applications 225, no. 34 (1994): 337–345.
Abstract: DC magnetization data of superconducting thin YBCO films, measured by means of a magnetometer in which the sample is pulled through a set of pickup coils, are often calculated from pickup signals which clearly deviate from the ideal response. We show how these signal distortions influence the values obtained for the magnetization, and present a simple model that enables one to simulate the temperature dependence of these distorted pickup signals, in the case of lowfield magnetization measurements. The model is based on the magnetic field inhomogeneity of the magnetometer, in combination with the hysteretic magnetization of the superconducting sample. Optimum values for the model parameters are derived and discussed.
