|
Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Science / Faculty of Science >
Peer-reviewed Journal Articles, etc >
Static and dynamic spin properties in the quantum triangular lattice antiferromagnet Ag2CoO2
| Title: | Static and dynamic spin properties in the quantum triangular lattice antiferromagnet Ag2CoO2 |
| Authors: | Yoshida, H. K. Browse this author →KAKEN DB | | Dissanayake, S. E. Browse this author | | Christianson, A. D. Browse this author | | dela Cruz, C. R. Browse this author | | Cheng, Y-Q Browse this author | | Okamoto, S. Browse this author | | Yamaura, K. Browse this author | | Isobe, M. Browse this author | | Matsuda, M. Browse this author |
| Issue Date: | 29-Jul-2020 |
| Publisher: | American Physical Society (APS) |
| Journal Title: | Physical Review B |
| Volume: | 102 |
| Issue: | 2 |
| Start Page: | 024445 |
| Publisher DOI: | 10.1103/PhysRevB.102.024445 |
| Abstract: | In Ag2CoO2, Co forms triangular lattice layers, which are separated by the metallic (Ag-2) block. The magnetic susceptibility and heat capacity measurements show that this material exhibits an antiferromagnetic transition at T-N = 17.5 K and the Weiss temperature (T-Theta) and the effective moment are -274 K and 1.62 mu(B), respectively, indicating that the Co ion carries spin (S) 1/2 and has a strongly frustrated state with T-Theta/T-N = 15.7. A density functional theory calculation confirmed that the valence state of the Co ions is 2+ and the low-spin state with S = 1/2 is realized at reduced on-site Coulomb interaction on Co. We performed elastic and inelastic neutron scattering experiments in a powder sample of Ag2CoO2. Although no noticeable magnetic Bragg peaks were observed below T-N, distinct magnetic excitations were observed in the inelastic neutron scattering experiments. The excitations are consistent with those expected for the S = 1/2 Heisenberg triangular lattice antiferromagnet. These results suggest that the ordered moment is reduced due to the quantum effect, which explains the absence of the magnetic Bragg peaks. Our results thus suggest that Ag2CoO2 is a good candidate to realize a quantum Heisenberg triangular lattice antiferromagnet. |
| Rights: | Copyright 2020 by The American Physical Society. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/79234 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
|
Submitter: 吉田 紘行
|
