Phononic and magnetic excitations in the quasi-one-dimensional Heisenberg antiferromagnet KCuF3

Автор(и)

  • V. Gnezdilov B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Lenin Ave., Kharkov 61103, Ukraine
  • J. Deisenhofer Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg, Germany
  • P. Lemmens Institute for Condensed Matter Physics, Braunschweig University of Technology, D-38106 Braunschweig, Germany
  • D. Wulferding Institute for Condensed Matter Physics, Braunschweig University of Technology, D-38106 Braunschweig, Germany
  • O. Afanasiev B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Lenin Ave., Kharkov 61103, Ukraine
  • P. Ghigna Dipartimento di Chimica Fisica, Universita di Pavia, 1-27100 Pavia, Italy
  • A. Loidl Dipartimento di Chimica Fisica, Universita di Pavia, 1-27100 Pavia, Italy
  • A. Yeremenko B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Lenin Ave., Kharkov 61103, Ukraine

DOI:

https://doi.org/10.1063/1.4709772

Ключові слова:

Raman scattering, low-dimensional magnetic systems, dynamical Dzyaloshinsky-Moriya interaction, magnetic excitations.

Анотація

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.

Завантаження

Дані завантаження ще не доступні.

Downloads

Опубліковано

2012-03-16

Як цитувати

(1)
Gnezdilov, V.; Deisenhofer, J.; Lemmens, P.; Wulferding, D.; Afanasiev, O.; Ghigna, P.; Loidl, A.; Yeremenko, A. Phononic and Magnetic Excitations in the Quasi-One-Dimensional Heisenberg Antiferromagnet KCuF3. Fiz. Nizk. Temp. 2012, 38, 538-548.

Номер

Розділ

Низькотемпературний магнетизм

Статті цього автора (авторів), які найбільше читають

<< < 1 2 3