CO₂‐Induced Strong Room‐Temperature Ferromagnetism in BiFeO₃

Abstract

Abstract With humongous demand for data storage and processing, two‐dimensional (2D) ferromagnetic‐based materials, is emerged as the next‐generation nanoelectronic devices due to their low power consumption and optimal memory and processing capabilities. BiFeO 3 as a single‐phase multiferromagnetic material is expected to find potential applications in electromagnetic devices. Herein, 2D room‐temperature ferromagnetic BiFeO 3 is obtained with the help of supercritical carbon dioxide (SC CO 2 ). The rhombic phase of BiFeO 3 is converted to cubic with the creation of O v and Fe 2+ defects over the SC CO 2 treatment, leading to significant ferromagnetic enhancement. More importantly, it is found that SC CO 2 can destroy the cycloidal spin structure of BiFeO 3 leading to an increase in the Fe─O─Fe bond angle, which generates stronger superexchange interactions. Ultimately, the saturation magnetization strength of BiFeO 3 is increased by nearly 23 times. A new strategy is provided for ferromagnetic induction in 2D materials, which is favorable for promoting their practical applications on device architectures in the future.