Abstract
The dipolar-octupolar (DO) pyrochlores, R2M2O7 (R=Ce,Sm,Nd), are key players in the search for realizable novel quantum spin liquid (QSL) states as a large parameter space within the DO pyrochlore phase diagram is theorized to host QSL states of both dipolar and octupolar nature. New single crystals and powders of Ce2Sn2O7, synthesized by hydrothermal techniques, present an opportunity for a new characterization of the exchange parameters in Ce2Sn2O7 using the near-neighbor XYZ model Hamiltonian associated with DO pyrochlores. Utilizing quantum numerical linked cluster expansion fits to heat capacity and magnetic susceptibility measurements, and classical Monte Carlo calculations to the diffuse neutron diffraction of the new hydrothermally grown Ce2Sn2O7 samples, we place Ce2Sn2O7's ground state within the ordered dipolar all-in-all-out (AIAO) Néel phase, with quantum Monte Carlo calculations showing a transition to long-range order at temperatures below those accessed experimentally. Indeed, our new neutron diffraction measurements on the hydrothermally grown Ce2Sn2O7 powders show a broad signal at low scattering wave vectors, reminiscent of a dipolar spin ice, in striking contrast from previous powder neutron diffraction on samples grown from solid-state synthesis, which found diffuse scattering at high scattering wave vectors associated with magnetic octupoles and suggested an octupolar quantum spin ice state. We conclude that new hydrothermally grown Ce2Sn2O7 samples host a finite-temperature proximate dipolar spin ice phase, above the expected transition to AIAO Néel order.
| Original language | English |
|---|---|
| Article number | 011005 |
| Journal | Physical Review X |
| Volume | 14 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2024 |
Funding
The authors thank V. Porée and R. Sibille for useful discussions and providing experimental data for comparison. We also thank J. Liu for performing the mail-in experiment at the NOMAD beam line at ORNL. D. R. Y. acknowledges useful discussions with J. Paddison. This research used resources at the High Flux Isotope Reactor and the Spallation Neutron Source at Oak Ridge National Laboratory, which was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, U.S. Department of Energy. D. R. Y and S. C. acknowledge support from the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under Contract No. DE-SC0014664. D. R. Y., K. A. R., M. P., and J. W. K. acknowledge funding from the Department of Energy Award No. DE-SC0020071. Specific heat and magnetization measurements by A. F. M. and C. M. P. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. This work was partly supported by the Deutsche Forschungsgemeinschaft under Grant No. SFB 1143 (Project No. 247310070) and the cluster of excellence ct.qmat (EXC 2147, Project No. 390858490). Additionally, this work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).
| Funders | Funder number |
|---|---|
| Office of Basic Sciences | |
| Office of Science Graduate Student Research | |
| SCGSR | |
| Scientific User Facilities Division | |
| U.S. Department of Energy | DE-SC0020071, DE-SC0014664 |
| Office of Science | |
| Basic Energy Sciences | |
| Workforce Development for Teachers and Scientists | |
| Oak Ridge Institute for Science and Education | |
| Division of Materials Sciences and Engineering | |
| Natural Sciences and Engineering Research Council of Canada | |
| Deutsche Forschungsgemeinschaft | EXC 2147, 247310070, 390858490, SFB 1143 |