Vale, J. G.Boseggia, S.Walker, H. C.Springell, R. S.Hunter, E. C.Perry, R. S.Collins, S. P.McMorrow, D. F.2019-06-182019-06-182019-06-182019-05-0810.1088/1361-648X/ab0471https://infoscience.epfl.ch/handle/20.500.14299/158043WOS:000460528700002X-ray magnetic critical scattering measurements and specific heat measurements were performed on the perovskite iridate Sr3Ir2O7. We find that the magnetic interactions close to the Neel temperature T-N = 283.4(2) K are three-dimensional. This contrasts with previous studies which suggest two-dimensional behaviour like Sr2IrO4. Violation of the Harris criterion (d nu > 2) means that weak disorder becomes relevant. This leads a rounding of the antiferromagnetic phase transition at T-N, and modifies the critical exponents relative to the clean system. Specifically, we determine that the critical behaviour of Sr3Ir2O7 is representative of the diluted 3D Ising universality class.Physics, Condensed MatterPhysicsmagnetic critical scatteringiridatesphase transitions2 length scalesx-ray-scatteringtext::journal::journal article::research article