High-pressure supercritical CO₂-assisted fabrication of two-dimensional LaAlO₃ and its room temperature ferromagnetism

Abstract Spintronics applications in two-dimensional (2D) magnetic materials can significantly contribute to the miniaturization and energy efficiency of semiconductor devices. However, current 2D ferromagnetic materials face challenges such as ferromagnetic instability and low Curie temperature (Tc), which limit their broader application. In this study, 2D room-temperature ferromagnetic LaAlO₃ was successfully prepared with supercritical carbon dioxide (SC CO₂). With the enhanced stress effect of CO₂ molecules, the contents of oxygen vacancies O_V, aluminium vacancies Al_V, and AlO₄ in the 2D structure are elevated, and then the ferromagnetic properties of LaAlO₃ appeared to be significantly enhanced due to defects and spatial symmetry breaking of the octahedron. Notably, the 2D intrinsic ferromagnetic LaAlO₃ exhibited a Tc above 350 K. Therefore, this work supplies a new means for SC CO₂ to modulate the microstructure and ferromagnetic properties of 2D LaAlO₃, which is conducive to expanding the applications of LaAlO₃.