High-sensitivity laminated magnetoelectric sensors without bias in composite of positive/negative giant magnetostrictive materials and piezoelectric single crystals

Low-frequency and resonance magnetoelectric (ME) responses without bias have been studied in a three-phase multilayer ME composite consisting of positive/negative giant magnetostrictive materials (GMMs) Terfenol-D (Tb0.3Dy0.7Fe1.92), Samfenol (SmFe2) plates, and piezoelectric single crystal 0.67PMN-0.33PT [0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3]. The large intrinsic anisotropic field with obvious hysteresis and remnant magnetization in SmFe2 plates as well as an exchanging field induced by the differences in magnetic properties of the two GMMs contributes to the self-biased ME responses. The experimental results demonstrate that the output sensitivities without bias for the resonance frequency at 97.5 kHz and the off-resonance frequency at 1 kHz can reach 1.1 V/Oe and 8.7 mV/Oe, respectively. A step change of ac magnetic field as small as ∼2.27 × 10−8 T can be clearly distinguished by the amplitude of the output signals under the resonance frequency of 97.5 kHz. These results provide potential applications for magnetic field detection without bias by utilizing a multilayer ME laminate due to its self-biased, self-powered, and ultra-sensitive properties.