High‐Entropy Enhanced Microwave Attenuation in Titanate Perovskites

Abstract

AbstractHigh‐entropy oxides (HEOs), which incorporate multiple‐principal cations into single‐phase crystals and interact with diverse metal ions, extend the border for available compositions and unprecedented properties. Herein, a high‐entropy‐stabilized (Ca0.2Sr0.2Ba0.2La0.2Pb0.2)TiO3 perovskite is reported, and the effective absorption bandwidth (90% absorption) improves almost two times than that of BaTiO3. The results demonstrate that the regulation of entropy configuration can yield significant grain boundaries, oxygen defects, and an ultradense distorted lattice. These characteristics give rise to strong interfacial and defect‐induced polarizations, thus synergistically contributing to the dielectric attenuation performance. Moreover, the large strains derived from the strong lattice distortions in the high‐entropy perovskite offer varied transport for electron carriers. The high‐entropy‐enhanced positive/negative charges accumulation around grain boundaries and strain‐concentrated location, quantitatively validated by electron holography, results in unusual dielectric polarization loss. This study opens up an effective avenue for designing strong microwave absorption materials to satisfy the increasingly demanding requirements of advanced and integrated electronics. This work also offers a paradigm for improving other interesting properties for HEOs through entropy engineering.