Magnetic and structural properties of the iron oxychalcogenides La2O2Fe2OM2(M=S,Se)

Author(s): Freelon, B; Yamani, Z; Swainson, I; Flacau, R; Karki, B; Liu, YH; Craco, L; Laad, MS; Wang, M; Chen, J; Birgeneau, RJ; Fang, M | Abstract: © 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. We present the results of structural and magnetic phase comparisons of the iron oxychalcogenides La2O2Fe2OM2(M=S,Se). Elastic neutron scattering reveals that M=S and Se have similar nuclear structures at room and low temperatures. Our neutron diffraction data reveals that both materials obtain antiferromagnetic ordering at a Neel temperature TN90.1±0.16 K and 107.2±0.06 K for M=Se and S, respectively. The magnetic arrangements for both M=S, Se compounds are obtained through Rietveld refinement. We find the order parameter exponent β to be 0.129±0.006 for M=Se and 0.133±0.007 for M=S. Each of these values is near the Ising symmetry value of 1/8. This suggests that although lattice and electronic structural modifications result from chalcogen replacement, the nature of the magnetic interactions is similar in these materials.