Domain engineering via AlN compositing in high-entropy ferroelectric ceramics for synergistic electro-thermal regulation

Abstract

Ferroelectrics enable active thermal management via electric-field switching, but low thermal conductivity and switching ratio limit practical use. Our work demonstrates domain engineering in high-entropy Pb(Zr,Ti)O₃-based ceramics by AlN compositing via two-step sintering. AlN addition refines the matrix grain size, induces lattice strain, and promotes the formation of a pyrochlore phase at high contents. Piezoelectric force microscopy reveals reduced domain wall density and enlarged domains due to interfacial defect-induced internal bias fields. Electrically, remnant polarization P_r decreases, while coercive field E_c and Curie temperature T_C exhibit non-monotonic evolution, reflecting a transition from domain wall pinning to leakage- and internal field-dominated regimes. Thermally, enhanced thermal conductivity competes with a reduced switching ratio, with a critical composition at 6 mol% AlN where maximized interfacial phonon scattering yields a localized improvement in thermal switching efficiency. AlN incorporation enables synergistic control of ferroelectric stability and thermal transport through grain refinement, internal field, and domain restructuring. Our work provides fundamental insights into domain–electrothermal coupling in ferroelectric composites.