Relaxation dynamics in the frustratedCr9antiferromagnetic ring probed by NMR
| Autor: | Stefano Carretta, Grigore A. Timco, Alessandro Lascialfari, R. E. P. Winpenny, S. Bordignon, R. De Renzi, Yuji Furukawa, Giuseppe Amoretti, Giuseppe Allodi, Paolo Santini, E. Garlatti, Robert J. Woolfson |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
Condensed matter physics Geometrical frustration Degenerate energy levels 02 engineering and technology 021001 nanoscience & nanotechnology Ring (chemistry) 01 natural sciences Magnetic field Magnetization 0103 physical sciences Relaxation (physics) Antiferromagnetism Condensed Matter::Strongly Correlated Electrons 010306 general physics 0210 nano-technology Ground state |
| Zdroj: | Physical Review B. 93 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.93.024424 |
| Popis: | We investigate the magnetic properties and the phonon-induced relaxation dynamics of the first regular ${\mathrm{Cr}}_{9}$ antiferromagnetic (AF) ring, which represents a prototype frustrated AF ring. Geometrical frustration in ${\mathrm{Cr}}_{9}$ yields an energy spectrum with twofold degenerate low-lying levels and a low-spin ground state. The electronic relaxation dynamics is probed by ${}^{1}\mathrm{H}$-NMR through the temperature dependence of the spin-lattice relaxation rate $1/{T}_{1}$. We develop a microscopic model that reproduces $1/{T}_{1}(T)$ curves, taking also into account the wipeout effect. By interpreting these measurements we determine the spin-phonon coupling strength and we investigate the decay of the cluster magnetization due to the spin-phonon interaction. We find that at very low temperatures, the relaxation is characterized by a single dominating Arrhenius-type relaxation process, whereas several relevant processes emerge at higher temperatures. In addition, we calculate the temperature and magnetic field dependence of level lifetimes. |
| Databáze: | OpenAIRE |
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