Adaptive Chemical Strain Boundary in Freestanding BiSmFe2O6 Double-Perovskite Membranes

en Double-perovskite multiferroic systems have attracted increasing attention due to their highly tunable structures and chemical adaptability. The uncontrollable performance changes caused by the release of boundary conditions are an important factor hindering the development of freestanding membranes. Here, the freestanding BiSmFe 2 O 6 (BSFO) double-perovskite membranes with a fixed mechanical boundary are proposed, leveraging adaptive chemical modification, a distortion that breaks intrinsic properties, during the boundary creation process. This is attributed to the tendency of film systems with abnormal Poisson deformation to develop chemical strain during the lattice volume change process. We employ electrodynamic decomposition, an approach enabling intact release of wrinkle-free membranes, which enhances the quality of freestanding membranes and the controllability of the mechanical boundary. Compared to the epitaxial films, the freestanding BSFO double-perovskite membranes retain the same ferroelectric origin and lattice parameters, with comparable electrical and optical behaviors, all reflecting the preservation of the about 5.06 GPa chemical strain boundary post-peeling. These findings underscore the effectiveness of adaptive chemical modulation in achieving constant mechanical boundary conditions for strained materials with outstanding performance. 摘要 zh 双钙钛矿多铁体系因其高度可调的结构和优异的化学适配性,已引起学术界的广泛关注。自支撑薄膜的边界条件释放引发的性能不可控变化是制约其发展的关键因素。本文提出一种通过自适应化学调控策略制备具有固定机械边界的自支撑BiSmFe 2 O 6 (BSFO)双钙钛矿薄膜的方法,该策略可有效抑制边界构建过程中因结构畸变导致的本征性能改变。这一现象源于,在具有反常泊松形变特性的薄膜体系中,晶格体积变化易形成化学应变的内在趋势。研究采用电动力学分解技术,实现了无褶皱双钙钛矿薄膜的完整剥离,显著提升了自支撑薄膜的品质与机械边界的可控性。与外延薄膜相比,所制备的自支撑BSFO 双钙钛矿薄膜不仅保留了相同的铁电起源与晶格参数,其电学及光学性能亦具有良好的一致性,这一结果证实剥离后薄膜仍维持约 5.06 GPa 的化学应变边界。本研究为实现应变功能材料的恒定机械边界调控及优异性能保留提供了有效的自适应化学调控路径,具有重要的应用前景。