Observation of an inter-sublattice exchange magnon in CoCr$_2$O$_4$ and analysis of magnetic ordering
| Autor: | Kamenskyi, D., Engelkamp, H., Fischer, T., Uhlarz, M., Wosnitza, J., Gorshunov, B. P., Komandin, G. A., Prokhorov, A. S., Dressel, M., Bush, A. A., Torgashev, V. I., Pronin, A. V. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | PRB 87, 134423 (2013) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.87.134423 |
| Popis: | We report on an investigation of optical properties of multiferroic CoCr$_{2}$O$_{4}$ at terahertz frequencies in magnetic fields up to 30 T. Below the ferrimagnetic transition (94 K), the terahertz response of CoCr$_{2}$O$_{4}$ is dominated by a magnon mode, which shows a steep magnetic-field dependence. We ascribe this mode to an exchange resonance between two magnetic sublattices with different $g$-factors. In the framework of a simple two-sublattice model (the sublattices are formed by Co$^{2+}$ and Cr$^{3+}$ ions), we find the inter-sublattice coupling constant, $\lambda = - (18 \pm 1)$ K, and trace the magnetization for each sublattice as a function of field. We show that the Curie temperature of the Cr$^{3+}$ sublattice, $\Theta_{2}$ = $(49 \pm 2)$ K, coincides with the temperature range, where anomalies of the dielectric and magnetic properties of CoCr$_{2}$O$_{4}$ have been reported in literature. Comment: accepted to PRB |
| Databáze: | arXiv |
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