Micromechanical Instruments for Ferromagnetic Measurements
John M. Moreland
I review some of the novel methods for measuring ferromagnetic properties of thin films based on micromechanical magnetometers. Measurements rely on the detection of mechanical forces or torques on samples deposited onto microcantilevers. Displacements of the cantilever are detected by optical methods similar to those developed for atomic force microscopy. High sensitivities are achieved by integrating the sample with the detector, allowing magnetic measurements of samples with a total magnetic moment smaller than that detectable with conventional magnetometers. Cantilevers with low spring constants and high mechanical Q are essential for these measurements. Sensitivities better than 105 υB are possible at room temperature with the potential for single spin detection below 1 K, where the thermomechanical noise of micromechanical sensors is substantially reduced.