Theoretical and experimental investigations on the resonance frequency shift characteristic of a ferromagnetic plate

Abstract

The theoretical as well as experimental investigations on the resonance frequency shift characteristic of a ferromagnetic plate in an inclined magnetic field are presented. A magnetic traction on the interface between a ferromagnetic material and the air is derived. An analytical model with the nonlinear law of magnetization is proposed for the field-dependent resonance frequency of a ferromagnetic plate. Model predictions show good correlation with the experimental data at different inclined angles. Both the theoretical and experimental investigations show that there exists a critical angle of the inclined field, below which the resonance frequency of the ferromagnetic plate will increase with the magnetic field, and above which the frequency will decrease with increasing the field. The critical angle predicted by the model, which is 86°, is exactly in the range revealed by experiments. Furthermore, the predictions show that the critical angle is sensitive to the length-to-thick ratio of the plate.