GdWN_3 is a Nitride Perovskite

Nitride perovskites ABN_3 are an emerging and highly under-explored classof materials that are of interest due to their intriguing calculatedferroelectric, optoelectronic, and other functional properties. Incorporatingnovel A-site cations is one strategy to tune and expand such properties; forexample, Gd^3+ is compelling due to its large magnetic moment, potentiallyleading to multiferroic behavior. However, the theoretically predicted groundstate of GdWN_3 is a non-perovskite monoclinic structure. Here, weexperimentally show that GdWN_3 crystallizes in a perovskite structure.High-throughput combinatorial sputtering with activated nitrogen is employed tosynthesize thin films of Gd_1-xW_xN_3-y with low oxygen contentwithin the bulk of the films. Ex-situ annealing crystallizes a polycrystallineperovskite phase in a narrow composition window near x=1. LeBail fits ofsynchrotron grazing incidence wide angle X-ray scattering data are consistentwith a perovskite ground-state structure. New density functional theorycalculations that included antiferromagnetic configurations confirm that theground-state structure of GdWN_3 is a distorted Pnma perovskite withantiferromagnetic ordering, in contrast to prior predictions. Initial propertymeasurements find that GdWN_3 is paramagnetic down to T=2 K withantiferromagnetic correlations and that the absorption onset depends on cationstoichiometry. This work provides an important stepping stone towards the rapidexpansion of the emerging family of nitride perovskites and towards ourunderstanding of their potential multiferroic properties.