Temperature-dependent magnetoelectric response of lead-free Na0.4K0.1Bi0.5TiO3/NiFe2O4-laminated composites

This study investigates the temperature-dependent quasi-static magnetoelectric (ME) response (alpha E) of electrically poled lead-free Na0.4K0.1Bi0.5TiO3-NiFe2O4 (NKBT-NFO)-laminated composites. The aim is to understand the temperature stability of ME-based sensors and devices. The relaxor ferroelectric nature of NKBT is confirmed through impedance and polarization-electric (PE) hysteresis loop studies, with a depolarization temperature (T-d) of approximately 110 degrees C. Heating causes a decrease and disappearance of planar electromechanical coupling (K-p), charge coefficient (d(31)), and remnant polarization (P-r) above T-d. The temperature rise to 125 degrees C also leads to a reduction in magnetostriction (lambda) and magnetostriction coefficient (q = d lambda/dH) of NFO by approximately 33% and 25%, respectively. At room temperature, the bilayer and trilayer configurations exhibit maximum ME responses of approximately 33 mV/cm<middle dot>Oe and 80 mV/cm<middle dot>Oe, respectively, under low magnetic field conditions (H similar to 300-450 Oe). The ME response of NKBT/NFO is highly sensitive to temperature, decreasing with heating in accordance with the individual temperature-dependent properties of NKBT and NFO. This study demonstrates a temperature window for the effective utilization of NKBT/NFO-based laminated composite ME devices.