Abstract
Ba3Yb2Zn5O11 is exceptional among breathing pyrochlore compounds for being in the nearly-decoupled limit where inter-tetrahedron interactions are weak, hosting isolated clusters or molecular magnet-like tetrahedra of magnetic ytterbium (Yb3+) ions. In this work, we present the study carried out on single-crystal samples of the breathing pyrochlore Ba3Yb2Zn5O11, using a variety of magnetometry and neutron scattering techniques along with theoretical modeling. We employ inelastic neutron scattering to investigate the magnetic dynamics as a function of applied field (with respect to both magnitude and direction) down to a temperature of 70 mK, where inelastic scattering reveals dispersionless bands of excitations as found in earlier powder sample studies, in good agreement with a single-tetrahedron model. However, diffuse neutron scattering at zero field and dc-susceptibility at finite field exhibit features suggesting the presence of excitations at low-energy that are not captured by the single tetrahedron model. Analysis of the local structure down to 2 K via pair distribution function analysis finds no evidence of structural disorder. We conclude that effects beyond the single tetrahedron model are important in describing the low-energy, low-temperature physics of Ba3Yb2Zn5O11, but their nature remains undetermined.
| Original language | English |
|---|---|
| Article number | 77 |
| Journal | npj Quantum Materials |
| Volume | 7 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2022 |
Funding
We are thankful to Stephen Kuhn for fruitful discussions and for his help with this project in its early stages. We are thankful to William W. Brennessel and the X-ray Crystallographic Facility of the Department of Chemistry at the University of Rochester for their help with single-crystal X-ray diffraction measurements. M.J.P.G. acknowledges the Canada Research Chair (Tier I) program for support. S.H. acknowledges the support provided by funding from William M. Fairbank Chair in Physics at Duke University, and from the Powe Junior Faculty Enhancement Award. This research used resources at the High Flux Isotope Reactor and Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. We acknowledge the support of the National Institute of Standards and Technology, U.S. Department of Commerce, in providing the neutron research facilities used in this work. The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR1157490 and DMR-1644779, the State of Florida and the U.S. Department of Energy.