Noise and scale effects on the signal-to-noise ratio in magnetoelectric laminate sensor/detection units

We have investigated the output noise level (E-no) and signal-to-noise ratio (SNR) for various magnetoelectric (ME) laminate composites. Our findings show (i) that E-no is nearly independent of materials couple or operational mode and practically determined by the laminate capacitance C and (ii) that the SNR has a scale effect, where it is limited by the volume (V) of the piezoelectric layer. Relations between SNR, V, and the magnetoelectric coefficient (alpha ME) give insights into how to construct ME sensors with enhanced sensitivity to small magnetic variation. (C) 2007 American Institute of Physics.