Magnetic dissipation and fluctuations in individual nanomagnets measured by ultrasensitive cantilever magnetometry

Cantilever magnetometry with resolution better than 104μB was used to study the moment, anisotropy, and switching behavior of single particles and nanowires. The spectral density of transverse magnetic fluctuations at the cantilever resonance frequency was determined based on the fluctuation-dissipation theorem. In general, striking differences in the magnitude of fluctuations in cobalt nanowires relative to individual rare-earth alloy particles were found.