Columnar microstructure of nanocrystalline Ga1−xMnxN films deposited by reactive sputtering

► Nanocrystalline GaMnN films with high Mn content grown by reactive sputtering. ► Morphology characterisation by XRD, TEM, HRTEM, EFTEM, and EDS. ► Textured columnar structure correlated with anisotropic growth and plasma process. ► Mn incorporation responsible for decreasing the growth anisotropy. ► Absence of Mn aggregates or any other secondary phase.