CO2-Induced Exposure of the Intrinsic Magnetic Surface of BaTiO3 to Give Room-Temperature Ferromagnetism

Preparation of low-dimensional ferromagnetic nanomaterials and investigation of their magnetic origin is critical to the exploration of novel materials with various applications such as data storage. Herein, non-van der Waals (non-vdW) BaTiO3 was successfully stripped to a low-dimensional structure by treating the materials with supercritical CO2 (SC CO2). Under different CO2 pressures, SC CO2 selectively cleaves the covalent bonds of the bulk BaTiO3, leading to the exposure of various surfaces. After SC CO2 treatments, the BaTiO3 exhibits room-temperature ferromagnetism, which is significantly stronger than conventional treatments. According to the experimental and theoretical investigations, the enhanced ferromagnetic property is attributed to the exposure of the intrinsic surfaces of BaTiO3.