Nanomechanical AC susceptometry of an individual mesoscopic ferrimagnet

•A nanomechanical AC susceptometer is reported.•AC susceptibility and DC magnetization were measured for a single YIG disk.•The technique involves RF mixing with two orthogonally applied AC fields.•Up to the 7th order harmonic of the AC susceptibility was identified.•The AC method highlights non-hysteric, nonlinear response.

A novel method for simultaneous detection of both DC and time-dependent magnetic signatures in individual mesoscopic structures has emerged from early studies in spin mechanics. Multifrequency nanomechanical detection of AC susceptibility and its harmonics highlights reversible nonlinearities in the magnetization response of a single yttrium iron garnet (YIG) element, separating them from hysteretic jumps in the DC magnetization.