Magnetodielectic Effect in Tri-layered Co65Fe35B20/PVDF/Co65Fe35B20 Composite Materials. Prediction and Measurement for Tunable Microwave Applications

Abstract : The variation of the permeability of a multilayered PVDF/CoFeHfN (piezoelectric/magnetostrictive) composite material under the action of a DC voltage is demonstrated. The driven-voltage permeability is first predicted using a finite element method-based multiphysics calculation. The simulation allows us to determine a magnetic anisotropy field of 45 Oe induced in the ferromagnetic layers by the mechanical coupling between magnetostrictive and piezoelectric layers due to the applied DC voltage. A variation of 30% for the permeability of the ferromagnetic layers is then measured using a radio-frequency permeameter and under the application of a DC voltage of 15V applied on the ferromagnetic layers which also act as electrodes for the bias of the PVDF. An additional measurement of the trilayer structure under the application of a magnetic field is finally performed to evaluate the magnetic field needed to get a 30% variation of the magnetic layers permeability in order to compare this value with the one predicted by multiphysics calculation. These experimental results are in good agreement with calculations and are very encouraging for the application of the CoFeHfN/PVDF/CoFeHfN composite material to insure the tunability of microwave devices (filters, phase shifters, antennas, etc.)