Ferromagnetism in tetragonally distorted chromium

We report on the experimental observation of ferromagnetic ordering in the tetragonally distorted alpha phase of Cr, based on the anomalous Hall effect hysteresis and corroborated by magnetization hysteresis. The ferromagnetic ordering is reasonably ascribed to an increase in the out-of-plane lattice parameter of the alpha-Cr phase due to the low-dimensional connection to the delta-Cr crystal-lattice matrix, which suffers a large compressive lattice-mismatch strain from the substrate under two-dimensional growth. The low proportion of the alpha phase in the Cr film results in a weak macroscopic-scale ferromagnetic moment.