Phononic and magnetic excitations in the quasi-one-dimensional Heisenberg antiferromagnet KCuF₃
Vernadsky National Library of Ukraine
Переглянути архів Інформація| Поле | Співвідношення | |
| Title |
Phononic and magnetic excitations in the quasi-one-dimensional Heisenberg antiferromagnet KCuF₃
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| Creator |
Gnezdilov, V.
Deisenhofer, J. Lemmens, P. Wulferding, D. Afanasiev, O. Ghigna, P. Loidl, A. Yeremenko, A. |
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| Subject |
Низкотемпеpатуpный магнетизм
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| Description |
The Raman-active phonons and magnetic excitations in the orbitally ordered, quasi-one-dimensional Heisenberg antiferromagnet KCuF₃ are studied as a function of temperature in the range between 3 and 290 K in various scattering configurations. The low-energy Eg and B1g phonon modes show an anomalous softening (~25% and ~13%) between room temperature and the characteristic temperature TS = 50 K. In this temperature range a freezing-in of F– ion dynamic displacements is proposed to occur. In addition, the Eg mode at about 260 cm⁻¹ clearly splits below TS. The widths of the phonon lines above TS follow an activated behavior with an activation energy of about 50 K. Our observations clearly evidence a reduction of the lattice symmetry below TS and indicate a strong coupling of lattice, spin, and orbital fluctuations for T > TS. A strongly polarization dependent quasielastic scattering is observed at temperatures above TN = 39 K due to magnetic-energy fluctuations. For temperatures below TN a rich spectrum of additional modes is observed, with different lineshape, polarization and temperatures dependence. We attribute them to longitudinal and transverse magnetic modes as well as to a continuum of magnetic excitations. |
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| Date |
2017-05-20T16:59:47Z
2017-05-20T16:59:47Z 2012 |
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| Type |
Article
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| Identifier |
Phononic and magnetic excitations in the quasi-one-dimensional Heisenberg antiferromagnet KCuF₃ / V. Gnezdilov, J. Deisenhofer, P. Lemmens, D. Wulferding, O. Afanasiev, P. Ghigna, A. Loidl, A. Yeremenko // Физика низких температур. — 2012. — Т. 38, № 5. — С. 538-548. — Бібліогр.: 66 назв. — англ.
0132-6414 PACS: 63.20.–e, 75.25.–j, 75.25.Dk, 75.50.–y, 78.30.–j http://dspace.nbuv.gov.ua/handle/123456789/117189 |
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| Language |
en
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| Relation |
Физика низких температур
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| Publisher |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
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