A Universal Laser‐Driven Controllable Synthesis Methodology Enabling Electromagnetic Absorption in High‐Entropy Rare‐Earth Oxides

Imparting electromagnetic absorption functionality is key to realizing integrated structural and functional applications of high-entropy rare-earth oxides (HEREOs). Here, a laser-driven controllable synthesis (LDCS) technique is reported to achieve this long-desired goal. Specifically, utilizing this approach, all polymorphs of high-entropy rare-earth disilicates (HEREDs), including unreported δ-, F-, and G-type phases with up to 20 principal elements are successfully synthesized. Crucially, it is demonstrated that a G-type 20-cation HERED is conferred with exceptional electromagnetic wave absorption: an effective absorption bandwidth profoundly broadened from 0.01 to 5.26 GHz. This enhancement is attributed to a laser-induced generation of extensive oxygen vacancies, which markedly increases conductance in electrical insulating HEREOs, and an exacerbation of nanointerface polarization loss caused by intensified local chemical order inherent to the incorporation of 20 constituent elements. The universality of this LDCS technique in enabling electromagnetic wave absorption across diverse HEREO families, including monosilicates, hafnates, zirconates, tantalates, niobates, and aluminates is finally verified, making them promising as radar stealth and thermal/environmental barrier integrated coating materials for use in hot section components of aircraft engines.