Charge states and lattice sites of Fe ions in virgin and Mn-doped Al x Ga 1− x N samples were investigated using 57 Fe emission Mössbauer spectroscopy following radioactive 57 Mn+ ion implantation at ISOLDE, CERN. In the undoped Al x Ga 1− x N, Fe 2+ on Al/Ga sites associated with nitrogen vacancies and Fe 3+ on substitutional Al/Ga sites are identified. With Mn doping, the contribution of Fe 3+ is considerably reduced and replaced instead by a corresponding emergence of a single-line-like component consistent with Fe 4+ on Al/Ga sites. Density functional theory calculations confirm the Fe 4+ charge state as stabilised by the presence of substitutional Mn 2+ in its vicinity. The completely filled spin up orbitals in Mn 2+(3d 5) are expected to enhance magnetic exchange interactions. The population of the Fe 4+ state is less pronounced at high Al concentration in Al x Ga 1− x N: Mn, a behaviour attributable to …