GdWN_3 is a Nitride Perovskite

Nitride perovskites ABN_3 are an emerging and highly under-explored class of materials that are of interest due to their intriguing calculated ferroelectric, optoelectronic, and other functional properties. Incorporating novel A-site cations is one strategy to tune and expand such properties; for example, Gd^3+ is compelling due to its large magnetic moment, potentially leading to multiferroic behavior. However, the theoretically predicted ground state of GdWN_3 is a non-perovskite monoclinic structure. Here, we experimentally show that GdWN_3 crystallizes in a perovskite structure. High-throughput combinatorial sputtering with activated nitrogen is employed to synthesize thin films of Gd_1-xW_xN_3-y with low oxygen content within the bulk of the films. Ex-situ annealing crystallizes a polycrystalline perovskite phase in a narrow composition window near x=1. LeBail fits of synchrotron grazing incidence wide angle X-ray scattering data are consistent with a perovskite ground-state structure. New density functional theory calculations that included antiferromagnetic configurations confirm that the ground-state structure of GdWN_3 is a distorted Pnma perovskite with antiferromagnetic ordering, in contrast to prior predictions. Initial property measurements find that GdWN_3 is paramagnetic down to T=2 K with antiferromagnetic correlations and that the absorption onset depends on cation stoichiometry. This work provides an important stepping stone towards the rapid expansion of the emerging family of nitride perovskites and towards our understanding of their potential multiferroic properties.