Magnetic transitions of hydrogenated HxCrO2 (x = 0 - 2) monolayer from a ferromagnetic half-metal to antiferromagnetic insulator.

We report the prediction of magnetic phase change in HxCrO2 (0 ≤ x ≤ 2) monolayer on the basis of first-principles calculations. As the H adsorption concentration x increases from 0 to 0.75, HxCrO2 monolayer transforms from a ferromagnetic (FM) half-metal to a small-gap FM insulator. When x = 1.00 and 1.25, it behaves as a bipolar antiferromagnetic (AFM) insulator, and eventually becomes an AFM insulator as x increases further up to 2.00. The results suggest that the magnetic properties of CrO2 monolayer can be effectively controlled by hydrogenation, and that HxCrO2 monolayers have the potential for realizing tunable two-dimensional magnetic materials.&#xD.