Magnetoelectric Performances in Composite of Piezoelectric Ceramic and Ferromagnetic Constant-Elasticity Alloy

A high-quality factor magnetoelectric (ME) laminated composite employing a type of ferromagnetic constant-elasticity alloy (FCEA) and piezoelectric Pb(Zr,Ti)O$_{3}$ material is developed. The laminate is designed to operate as a half-wavelength $(\lambda/2)$, longitudinal resonator. The FCEA features high effective quality factor and low magnetomechanical coupling coefficient. This induces a particular ME characteristic. The theoretical analysis shows that the ME voltage coefficient (MEVC) at low frequency is directly proportional to the product of the electromechanical coupling factor in piezoelectric layer, magnetomechanical coupling factor, and the square root of magnetic permeability in FCEA layers. The MEVC at resonance and the ME sensitivity (under resonant drive) to dc bias magnetic field $(H_{\rm dc})$ are dramatically increased by the effective quality factor $(Q_{m})$ of the resonator. The measured vibrational characteristics reveal that the strain coefficient at resonance achieves 314.74 nm/A and $Q_{m}$ is ${\sim} 1600$. The MEVC at resonance $(\alpha_{r})$ achieves 30.55 V/Oe (381.875 V/cm Oe), which is 1608 times higher than that at low frequency. In addition, $\alpha_{r}$ strongly depends on $H_{\rm dc}$ due to the high $Q_{m}$, e.g., $\partial \alpha_{r}/\partial H_{\rm dc}$ achieves 0.84 V/Oe$^{2}$. The ME resonator is potential for highly sensitive dc or quasi-static magnetic field sensing.