Abstract
We used single-crystal x-ray and neutron diffraction to investigate the crystal and magnetic structures of trigonal lattice iridate Ca2Sr2IrO6. The crystal structure is determined to be R3 with two distinct Ir sites. The system exhibits long-range antiferromagnetic order below TN=13.1 K. The magnetic wave vector is identified as (0,0.5,1) with ferromagnetic coupling along the a axis and antiferromagnetic correlation along the b axis. Spins align dominantly within the basal plane along the [1,2,0] direction and tilt 34 toward the c axis. The ordered moment is 0.66(3) μB/Ir, larger than other iridates where iridium ions form corner- or edge-sharing IrO6 octahedral networks. The tilting angle is reduced to ≈19 when a magnetic field of 4.9 T is applied along the c axis. Density functional theory calculations confirm that the experimentally determined magnetic configuration is the most probable ground state with an insulating gap ∼0.5 eV.
| Original language | English |
|---|---|
| Article number | 235116 |
| Journal | Physical Review B |
| Volume | 97 |
| Issue number | 23 |
| DOIs | |
| State | Published - Jun 11 2018 |
Funding
We thank G. Jackeli and J. M. Perez-Mato for stimulating discussion. Research at ORNL's SNS was sponsored by the Scientific User Facilities Division, Basic Energy Sciences, U.S. Department of Energy (DOE). Theoretical calculations were supported by the Materials Sciences and Engineering Division (SO), Office of Basic Energy Sciences, U.S. DOE, and through the Office of Science Early Career Research Program (VRC). Computing resources are from NERSC, supported by the office of science, U.S. DOE under Contract No. DE-AC02-05CH11231. Work at the University of Colorado was supported by the U.S. National Science Foundation via Grant No. DMR-1712101. J.M.S. acknowledges support from China Scholarship Council.