CO 2 Stress-Driven Room Temperature Ferromagnetism of Ultrathin 2D Gallium Oxide.

Spintronic devices work by manipulating the spin of electrons other than charge transfer, which is of revolutionary significance and can largely reduce energy consumption in the future. Herein, ultrathin two-dimensional (2D) non-van der Waals (non-vdW) γ-Ga 2 O 3 with room temperature ferromagnetism is successfully obtained by using supercritical CO 2 (SC CO 2 ). The stress effect of SC CO 2 under different pressures selectively modulates the orientation and strength of covalent bonds, leading to the change of atomic structure including lattice expansion, introduction of O vacancy, and transition of Ga-O coordination (GaO 4 and GaO 6 ). Magnetic measurements show that pristine γ-Ga 2 O 3 is nonferromagnetic, whereas the SC CO 2 treated γ-Ga 2 O 3 exhibits obvious ferromagnetic behavior with an optimal magnetization of 0.025 emu g -1 and a Curie temperature of 300 K.