Topochemical synthesis of cation ordered double perovskite oxynitrides

Topochemical nitridation in ammonia at moderate temperatures of cation ordered Sr2FeWO6 produces new antiferromagnetic double perovskite oxynitrides Sr2FeWO6-xNx with 0 < x ≤ 1. Nitrogen introduction induces the oxidation of Fe2+ to Fe3+ and decreases TN from 38 K (x = 0) to 13 K for Sr2FeWO5N which represents the first example of a double perovskite oxynitride with both high cationic order and nitrogen content. This synthetic approach can be extended to other cation combinations expanding the possibility of new materials in the large group of double perovskites.This work was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), Spain (Projects MAT2014-53500-R, MAT2015-71664-R, MAT2015-67593-P and ENE2015-63969) and it has been developed under the Materials Science PhD program of the Universitat Autònoma de Barcelona. Fellowship support to AB from MINECO (FPI, project MAT2011-24757) is gratefully acknowledged. ICMAB acknowledges financial support from MINECO through the Severo Ochoa Program (SEV- 2015-0496).Peer reviewe