| Full text | |
| Author(s): |
Sarkar, R.
;
Krizan, J. W.
;
Brueckner, F.
;
Andrade, E. C.
;
Rachel, S.
;
Vojta, M.
;
Cava, R. J.
;
Klauss, H. -H.
Total Authors: 8
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW B; v. 96, n. 23, p. 10-pg., 2017-12-12. |
| Abstract | |
We present results of Na-23 and F-19 nuclear magnetic resonance (NMR) measurements on NaCaCo2F7, a frustrated pyrochlore magnet with a Curie-Weiss temperature Theta(CW) approximate to -140 K and intrinsic bond disorder. Below 3.6 K both the Na-23 and F-19 spectra broaden substantially in comparison to higher temperatures accompanied by a considerable reduction (80%) of the NMR signal intensity: This proves a broad quasistatic field distribution. The F-19 spin-lattice relaxation rate (19)(1/T-1) exhibits a peak at 2.9 K already starting to develop below 10 K. We attribute the spin freezing to the presence of bond disorder. This is corroborated by large-scale Monte Carlo simulations of a classical bond-disordered XY model on the pyrochlore lattice. The low freezing temperature, together with the very short magnetic correlation length not captured by the simulations, suggests that quantum effects play a decisive role in NaCaCo2F7. (AU) | |
| FAPESP's process: | 13/00681-8 - Disordered magnets: ground state, excitations, and thermodynamics |
| Grantee: | Eric de Castro e Andrade |
| Support Opportunities: | Research Grants - Young Investigators Grants |