Emergent Uniaxial Magnetic Anisotropy in High-Integrity, Uniform Freestanding LaMnO<sub>3</sub> Membranes
Qing Wang, Qinwen Lu, X Zhang, Liuzhi Xiang, Long Cheng, Xiaolong Li, Hua Zhou, Xiaofang Zhai
Abstract
High Resolution Image Download MS PowerPoint Slide The water-liftoff fabrication of freestanding oxide membranes at nanometer-scale thickness marks a major breakthrough in expanding the family of soft electromagnetic materials. The structure reconstruction in the newly formed two-dimensional freestanding membrane due to the chemical liftoff provides an excellent opportunity to achieve applicable functionalities. In this report, we present the anisotropic relaxation of a LaMnO 3 epitaxial film into a nearly wrinkle- and crack-free membrane, realized by high-temperature (160 °C)-treated PMMA as the protective layer during the water liftoff process. Remarkably, the resulting membrane exhibits a 2-fold uniaxial magnetic anisotropy, which is in stark contrast to the typical 4-fold biaxial magnetic anisotropy in biaxially strained epitaxial thin films. By performing half-order synchrotron X-ray diffraction experiments, the membrane is found to exhibit almost unvaried Mn–O bond lengths but uniaxially enlarged Mn–O–Mn bond angles, agreeing with the uniaxial magnetic anisotropy. Our study paves the way for engineering macroscopically high-quality membranes free of wrinkles and cracks, unlocking emergent electromagnetic properties that are essential for the integration and application of functional devices.