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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Spin freezing in the disordered pyrochlore magnet NaCaCo2F7: NMR studies and Monte Carlo simulations

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Sarkar, R. [1] ; Krizan, J. W. [2] ; Brueckner, F. [1] ; Andrade, E. C. [3, 4] ; Rachel, S. [5, 6] ; Vojta, M. [5] ; Cava, R. J. [2] ; Klauss, H. -H. [1]
Total Authors: 8
[1] Tech Univ Dresden, Inst Festkorperphys, D-01062 Dresden - Germany
[2] Princeton Univ, Dept Chem, Princeton, NJ 08544 - USA
[3] Univ Estadual Paulista, Inst Fis Teor, Rua Dr Bento Teobaldo Ferraz 271, Bloco 2, BR-01140070 Sao Paulo - Brazil
[4] Univ Sao Paulo, Inst Fis Sao Carlos, Caixa Postale 369, BR-13560970 Sao Paulo - Brazil
[5] Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden - Germany
[6] Univ Melbourne, Sch Phys, Parkville, Vic 3010 - Australia
Total Affiliations: 6
Document type: Journal article
Source: Physical Review B; v. 96, n. 23 DEC 12 2017.
Web of Science Citations: 6

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 type: Research Grants - Young Investigators Grants