Shape-controlled synthesis of high-purity CrO2 under HTHP

High-purity CrO2 powders were prepared under high temperature (400 °C–600 °C) and high pressure (1 GPa–5 GPa) conditions. The shape, size and the grain boundary density of the CrO2 powders can be tuned via simply changing the experiment conditions, such as temperature and pressure. Magnetic properties of the CrO2 powders prepared under different conditions were investigated also. The saturation magnetizations of the samples are consistent with the best value ever reported. The synthesis of CrO2 powders with controlled morphology should be of interest in tunneling magnetoresistance research.