Voltage-Driven Nonlinearity in Magnetoelectric Heterostructures

Magnetoelectric (ME) heterostructures are widely studied to realize functional applications, such as magnetometers, ME random access memory (MERAM), ME antennas, energy harvesters, and voltage microwave devices. A good understanding of the nonlinearity of ME heterostructures can lead to potentially improved performance. Here, we present an investigation into the voltage-driven nonlinear phenomena of a ME heterostructure near its electromechanical resonance. The Stoner-Wohlfarth model and Duffing equation are used to study the ΔE effect in amorphous Metglas alloy and the nonlinear behavior of a ME heterostructure, respectively. Then, the dependence of the nonlinearity on bias field, driving voltage, mechanical quality factor, and the frequency sweeping direction are systematically studied and verified. Experimental results show that spring-hardening and -softening behavior is separately obtained at bias fields of 25 Oe and 50 Oe, respectively. In addition, hysteresis is observed when sweeping the frequency forward and then backward at a driving voltage of 5 V; this agrees well with qualitative analysis. This work provides a route to induce, control, and possibly exploit the nonlinear behavior of ME devices, such as magnetic-field energy harvesters and ME sensors and antennas.