Magnetic excitation spectrum of LuFe2O4 measured with inelastic neutron scattering
| Autor: | Gaw, S. M., Lewtas, H. J., McMorrow, D. F., Kulda, J., Ewings, R. A., Perring, T. G., McKinnon, R. A., Balakrishnan, G., Prabhakaran, D., Boothroyd, A. T. |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 91 (2015) 035103 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.91.035103 |
| Popis: | We report neutron inelastic scattering measurements and analysis of the spectrum of magnons propagating within the Fe2O4 bilayers of LuFe2O4. The observed spectrum is consistent with six magnetic modes and a single prominent gap, which is compatible with a single bilayer magnetic unit cell containing six spins. We model the magnon dispersion by linear spin-wave theory and find very good agreement with the domain-averaged spectrum of a spin-charge bilayer superstructure comprising one Fe3+ -rich monolayer and one Fe2+ -rich monolayer. These findings indicate the existence of polar bilayers in LuFe2O4, contrary to recent studies that advocate a charge-segregated non-polar bilayer model. Weak scattering observed below the magnon gap suggests that a fraction of the bilayers contain other combinations of charged monolayers not included in the model. Refined values for the dominant exchange interactions are reported. Comment: 12 pages, 9 figures |
| Databáze: | arXiv |
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