Strong Ferromagnetic Manipulation of SrTiO₃ from CO₂‐Straining Effect on Electronic Structure Modulation

Abstract

Abstract2D 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 SrTiO3 is achieved through straining effect induced by supercritical carbon dioxide (SC CO2). According to experimental results, the cubic phase of SrTiO3 is converted to tetragonal with exposure of (110), (200), (111), and (211) planes over the SC CO2 treatment, leading to significant ferromagnetic enhancement. Theoretical calculations illustrate that over the conversion from cubic to tetragonal, the electronic structure of SrTiO3 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 CO2, leading to magnetic optimizations. This work suggests that magnetic optimization can be achieved from SC CO2‐induced electronic structure modulation.