Strong Ferromagnetic Manipulation of SrTiO 3 from CO 2 -Straining Effect on Electronic Structure Modulation.

2D magnetic materials are ideal to fabricate magneto-optical, magneto-electric, and data storage devices, which are proposed to be critical to the next generation of information technologies. Benefited from their labile structures, 2D perovskites are amenable for magnetic manipulation through structural optimization. In this work, 2D room-temperature ferromagnetic SrTiO 3 is achieved through straining effect induced by supercritical carbon dioxide (SC CO 2 ). According to experimental results, the cubic phase of SrTiO 3 is converted to tetragonal with exposure of (110), (200), (111), and (211) planes over the SC CO 2 treatment, leading to significant ferromagnetic enhancement. Theoretical calculations illustrate that over the conversion from cubic to tetragonal, the electronic structure of SrTiO 3 is significantly modulated. Specifically, the spin density of planes of (200), (111), and (211) is enhanced, presumably due to the stabilization of the highest occupied molecular orbital over straining by SC CO 2 , leading to magnetic optimizations. This work suggests that magnetic optimization can be achieved from SC CO 2 -induced electronic structure modulation.