@article{discovery10134049, publisher = {AMER PHYSICAL SOC}, volume = {110}, month = {March}, note = {This version is the author accepted manuscript. For information on re-use, please refer to the publisher's terms and conditions.}, journal = {Physical Review Letters}, number = {11}, year = {2013}, title = {Robustness of Basal-Plane Antiferromagnetic Order and the J(eff)=1/2 State in Single-Layer Iridate Spin-Orbit Mott Insulators}, author = {Boseggia, S and Springell, R and Walker, HC and Ronnow, HM and Rueegg, C and Okabe, H and Isobe, M and Perry, RS and Collins, SP and McMorrow, DF}, abstract = {The magnetic structure and electronic ground state of the layered perovskite Ba 2 IrO 4 have been investigated using x-ray resonant magnetic scattering. Our results are compared with those for Sr 2 IrO 4 , for which we provide supplementary data on its magnetic structure. We find that the dominant, long-range antiferromagnetic order is remarkably similar in the two compounds and that the electronic ground state in Ba 2 IrO 4 , deduced from an investigation of the x-ray resonant magnetic scattering L 3 / L 2 intensity ratio, is consistent with a J eff = 1 / 2 description. The robustness of these two key electronic properties to the considerable structural differences between the Ba and Sr analogues is discussed in terms of the enhanced role of the spin-orbit interaction in 5 d transition metal oxides.}, url = {https://doi.org/10.1103/PhysRevLett.110.117207} }