A dual-peak phenomenon of magnetoelectric coupling in laminated Terfenol-D/PZT/Terfenol-D composites

Magnetoelectric (ME) composite materials find many applications due to their high magnetoelectric (ME) coefficient (alpha(ME)) at room temperature. A dual-peak phenomenon is reported in the curves of the magnetoelectric coefficient (alpha(ME)) versus the static magnetic field (H-S) for Terfenol-D/PZT/Terfenol-D tri-layered composites of rectangular shape. The first peak corresponds to the maximum of the piezomagnetic coefficient d(33,m) of the Terfenol-D plate, and the second is caused by the resonance of the laminate under the applied alternating magnetic field. The position of the first peak in the aME versus H-S curve shifts slightly as the frequency increases. The position of the second peak, however, moves considerably toward higher H-S values as the frequency increases. An analysis based on the equivalent circuit method is proposed, which incorporates the constitutive model and the change in Young's modulus with the applied static magnetic field (Delta E effect) for Terfenol-D. The theoretical prediction agrees well with the experimental observations. This finding is of importance for both the basic understanding of the ME composites and for device applications such as detection of magnetic materials.