Magnetic dead layer is not “magnetically dead” in hematite nanocubes

The presence of magnetic dead layer is usually supposed to cause a degradation of magnetism due to highly frustrated spin configurations. In this Letter, we report a diametrically opposite experimental and theoretical investigation as to hematite nanocubes, in which the magnetic dead layer, calculated to be 3.2nm-thick in average as for 25 nm-sized cubes, is found to be of high magnetic activity and hence dominating many of the cubesʼ magnetic features, including paramagnetic attribute of thermo-magnetic curves, good reversibility of high-field magnetization and obvious exchange bias effect in zero-field cooled procedure at low temperatures.