Antiferromagnetic resonance in methylaminated potassium fulleride(CH3NH2)K3C60
| Autor: | Matej Pregelj, Denis Arčon, Matthew J. Rosseinsky, Yasuhiro Takabayashi, Hans van Tol, Alexey Y. Ganin, Kosmas Prassides, Andrej Zorko, Louis-Claude Brunel |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Physical Review B. 77 |
| ISSN: | 1550-235X 1098-0121 |
| DOI: | 10.1103/physrevb.77.035104 |
| Popis: | High-frequency magnetic resonance measurements $({\ensuremath{\nu}}_{L}=9.6--420\phantom{\rule{0.3em}{0ex}}\mathrm{GHz})$ were employed to investigate the low-temperature antiferromagnetic ground state of the $(\mathrm{C}{\mathrm{H}}_{3}\mathrm{N}{\mathrm{H}}_{2}){\mathrm{K}}_{3}{\mathrm{C}}_{60}$ fulleride. The frequency and temperature dependence of the intensity, linewidth, and center of the resonance signal detected below ${T}_{N}$ are characteristic of antiferromagnetic resonance (AFMR). The AFMR intensity is consistent with an ordered magnetic moment of ${\ensuremath{\mu}}_{\mathit{eff}}=0.7(1){\ensuremath{\mu}}_{B}∕{\mathrm{C}}_{60}$, while the narrowing of the AFMR signal with increasing resonance frequency can be modeled with a spin-flop field of ${H}_{\mathit{sf}}=840(80)\phantom{\rule{0.3em}{0ex}}\mathrm{G}$ and a $g$-factor anisotropy of $\ensuremath{\delta}\ensuremath{\gamma}=710(50)\phantom{\rule{0.3em}{0ex}}\mathrm{ppm}$. We stress that the spin-flop field is reduced compared to the ammoniated analog $(\mathrm{N}{\mathrm{H}}_{3}){\mathrm{K}}_{3}{\mathrm{C}}_{60}$ on the account of reduced $\mathrm{C}_{60}{}^{3\ensuremath{-}}\text{\ensuremath{-}}\mathrm{C}_{60}{}^{3\ensuremath{-}}$ exchange interactions. Differences in the level of the anisotropic expansion between $\mathrm{C}{\mathrm{H}}_{3}\mathrm{N}{\mathrm{H}}_{2}$ and $\mathrm{N}{\mathrm{H}}_{3}$ cointercalated fullerides are likely to be responsible for the differences in the electronic structure between the two systems and ultimately may account for the reduced N\'eel temperature in $(\mathrm{C}{\mathrm{H}}_{3}\mathrm{N}{\mathrm{H}}_{2}){\mathrm{K}}_{3}{\mathrm{C}}_{60}$. |
| Databáze: | OpenAIRE |
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