Abstract
In frustrated spinel antiferromagnets, dilution with nonmagnetic ions can be a powerful strategy for probing unconventional spin states or uncovering interesting phenomena. Here, we present x-ray, neutron scattering, and thermodynamic studies of the effects of magnetic dilution of the tetragonally distorted A-site spinel antiferromagnet, CuRh2O4, with nonmagnetic Zn2+ ions. Our data confirm the helical spin order recently identified at low temperatures in this material, and further demonstrate a systematic suppression of the associated Néel temperature with increasing site dilution towards a continuous transition with critical doping of xspin∼0.44. Interestingly, this critical doping is demonstrably distinct from a second structural critical point at xJT∼0.6, which is consistent with the suppression of orbital order on the A site through a classical percolative mechanism. This anomalously low value for xspin is confirmed via multiple measurements, and is inconsistent with predictions of classical percolation theory, suggesting that the spin transition in this material is driven by an enhancement of preexisting spin fluctuations with weak dilution.
| Original language | English |
|---|---|
| Article number | 214411 |
| Journal | Physical Review B |
| Volume | 97 |
| Issue number | 21 |
| DOIs | |
| State | Published - Jun 11 2018 |
Funding
This work was sponsored by the National Science Foundation, under Grant No. DMR-1455264-CAR (G.J.M., A.V.Z., and S.G.). Synthesis, x-ray, and thermodynamic measurements were carried out in the Frederick Seitz Materials Research Laboratory Central Research Facilities, University of Illinois. Neutron scattering research at Oak Ridge National Laboratory's High Flux Isotope Reactor was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. This work was sponsored by the National Science Foundation, under Grant No. DMR-1455264-CAR (G.J.M., A.V.Z., and S.G.). Synthesis, x-ray, and thermodynamic measurements were carried out in the Frederick Seitz Materials Research Laboratory Central Research Facilities, University of Illinois. Neutron scattering research at Oak Ridge National Laboratory's High Flux Isotope Reactor was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.