  Otherwise antiferromagnetic chromium is shown to couple ferromagnetically
when doped into GaN irrespective of whether the host is a crystal or a cluster.
The results on the doped clusters and crystals are obtained from density
functional theory based molecular orbital theory and linearized muffin tin
orbital tight binding supercell band structure method respectively. The
calculated half metallic behavior of Cr-doped GaN crystal combined with the
observed room temperature Curie point make it an ideal candidate for
spintronics applications.
