Giant room-temperature magnetocapacitance in Terfenol-D/PZT/Terfenol-D trilayer composites

The giant room-temperature magnetocapacitance is reported in the Terfenol-D/PZT/Terfenol-D which is composed of a trilayer structure. A giant magnetocapacitance as large as 1200% is observed at the resonant frequency of 52.17 kHz and a saturated magnetic field of 1.5 kOe. We experimentally demonstrate that such magnetocapacitance effect correlates with the frequency shift of harmonic oscillator, i.e., PZT, which resulted from the applied magnetic field. In addition, theoretical analysis shows that the frequency shift is attributed to the product effects of the magnetic field-tuned Young's modulus of the Terfenol-D and the strain-capacitance of the ferroelectrics PZT. One can apply this characteristic of resonance frequency shift to design magnetocapacitance composites with a frequency-tunable magnetic filter.