Frontiers in Relaxor Antiferroelectric Thin Films: Understanding, Designing, and Energy‐Related Applications

The rapid evolution of functional oxides has revolutionized modern condensed matter physics and materials engineering, driven by their intricate spin-lattice-charge-orbital couplings and diverse functional properties. Among these, relaxor antiferroelectrics represent a prominent class of materials, distinguished by their unique second-order-like field-induced phase transitions and complex domain architectures. Unlike conventional antiferroelectrics, relaxor antiferroelectrics exhibit dynamic disorder and structural heterogeneity, offering unprecedented opportunities for electromechanical functionalities. This review systematically traces the evolution of antiferroelectrics from bulk to thin-film architectures and presents a critical analysis of state-of-the-art characterization techniques, such as advanced X-ray diffraction, scanning probe microscopy, and atomic-resolution transmission electron microscopy. A central focus lies in establishing design principles for high-performance relaxor antiferroelectric films, including interface engineering, structural heterogeneity, and chemical modification. The review further evaluates emerging energy-related applications spanning energy-storage capacitors, the electrocaloric effect, thermal switching, etc. Additionally, contemporary challenges and future prospects are highlighted, aiming to underscore novel research directions that will propel the advancement of antiferroelectrics and device designs. It is the earnest hope that this review will catalyze collaborative explorations into the unknown, fostering groundbreaking advancements in relaxor antiferroelectrics.