Critical fluctuations in the spin-orbit Mott insulator Sr$_3$Ir$_2$O$_7$

J. G. Vale; S. Boseggia; H. C. Walker; R. S. Springell; E. C. Hunter; R. S. Perry; S. P. Collins; D. F. McMorrow

doi:10.1088/1361-648X/ab0471

paper

Critical fluctuations in the spin-orbit Mott insulator Sr $_{3}$ Ir $_{2}$ O $_{7}$

arXiv:1812.08682 · doi:10.1088/1361-648X/ab0471

Abstract

X-ray magnetic critical scattering measurements and specific heat measurements were performed on the perovskite iridate Sr $_{3}$ Ir $_{2}$ O $_{7}$ . We find that the magnetic interactions close to the Néel temperature $T_{N}$ = 283.4(2) K are three-dimensional. This contrasts with previous studies which suggest two-dimensional behaviour like Sr $_{2}$ IrO $_{4}$ . Violation of the Harris criterion ( $d ν > 2$ ) 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 Sr $_{3}$ Ir $_{2}$ O $_{7}$ is representative of the diluted 3D Ising universality class.

Accepted in Journal of Physics: Condensed Matter

Critical fluctuations in the spin-orbit Mott insulator Sr3​Ir2​O7​

Abstract

Critical fluctuations in the spin-orbit Mott insulator Sr $_{3}$ Ir $_{2}$ O $_{7}$