Anisotropic antiferromagnetic order in triangle lattice Ca<sub>2</sub>Sr<sub>2</sub>IrO<sub>6 </sub>
ORAL
Abstract
The spin-orbit coupling (SOC) in the 5d iridates gives rise to a large variety of quantum phases such as Jeff=1/2 Mott insulating state. Due to the entanglement of spin and orbital degrees of freedom, the form of magnetic interactions depends closely on the underlying lattice geometry and could lead to novel magnetic ground states, for example, the weak ferromagnetism in the square lattice Sr2IrO4 with 180-degree Ir-O-Ir bond angle and proximity to the Kitaev model in the honeycomb lattice Na2IrO3 with 90-degree bond angle. We report neutron and x-ray diffraction studies of the magnetic order of the triangle lattice Ca2Sr2IrO6. In this system, individual Ir ions are well separated from each other and form nearly undistorted IrO6 octahedron. An antiferromagnetic order is observed below 13 K, with magnetic configuration breaking the 3-fold symmetry of the triangle lattice. The ordering moment is about 0.6 µB/site, larger than those of other iridates with strong connectivity between neighboring Ir ions. The anisotropic magnetic behavior highlights the important role of SOC in determining the magnetic ground state in this triangle lattice iridate.
*The work at U Colorado was supported by the National Science Foundation via grant DMR-1712101
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Presenters
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Feng Ye
- Neutron Scattering Division, Oak Ridge National Lab
- Oak Ridge National Lab
- Oak Ridge Nat'l Lab
- Oak Ridge National Laboratory