Preferences help
enabled [disable] Abstract
Number of results
2018 | 133 | 3 | 459-462
Article title

Are there Optical Magnons?

Title variants
Languages of publication
Optical magnons should occur in magnets containing two in-equivalent magnetic species only. However, Heisenberg interactions between in-equivalent magnetic atoms can be expected to be weak. This is because free exchange of electrons between chemically different magnetic atoms appears not generally possible. To the best of our knowledge optical magnons have never been identified unambiguously experimentally. Confusion is provided by the fact that two magnon branches commonly occur in antiferromagnets with ferromagnetically ordered crystallographic planes and opposite spin orientations from plane to plane. This applies to MnO, EuTe, CoCl₂, Fe₂O₃, K₂FeF₄. Associated with the ferromagnetic planes is a particular low-energy magnon branch. The high-energy magnon branch is the antiferromagnetic branch and not an optical magnon. In Fe₃O₄ (magnetite), weak interactions between the Fe²⁺ moments and the Fe³⁺ moments are evidenced by the fact that the order parameters of the FeO and of the Fe₂O₃ subsystem have different temperature dependencies. The observed two magnon branches can be attributed to the Fe₂O₃ and to the FeO subsystem, respectively. This applies equally to the two observed magnon branches in mixed crystals such as Rb₂Mn_{0.5}Ni_{0.5}F₄, KCo_{0.71}Mn_{0.29}F₃ or Mn_{0.3}Co_{0.7}F₂ that can be understood as modified dispersions of the constituent materials.
  • Research Centre Jülich, Institute PGI, 52425 Jülich, Germany
  • [1] U. Köbler, Acta Phys. Pol. A 127, 1694 (2015), doi: 10.12693/APhysPolA.127.1694
  • [2] K.G. Wilson, J. Kogut, Phys. Rep. 12C, 75 (1974), doi: 10.1016/0370-1573(74)90023-4
  • [3] A. Hoser, U. Köbler, Acta Phys. Pol. A 127, 350 (2015), doi: 10.12693/APhysPolA.127.350
  • [4] A. Hoser, U. Köbler, J. Physics: Conf. Series 746, 012062 (2016), doi: 10.1088/1742-6596/746/1/012062
  • [5] B.V. Karpenko, A.V. Kuznetsov, V.V. Dyakin, J. Magn. Magn. Mater. 117, 317 (1992), doi: 10.1016/0304-8853(92)90087-5
  • [6] M.P.H. Thurlings, E. Frikkee, H.W. de Wijn, Phys. Rev. B 25, 4750 (1982), doi: 10.1103/PhysRevB.25.4750
  • [7] G. Pepy, J. Phys. Chem. Solids 35, 433 (1974), doi: 10.1016/S0022-3697(74)80037-5
  • [8] J. Magarińo, J. Tuchendler, A.R. Fert, J. Gelard, Sol. State Commun. 23, 175 (1977), doi: 10.1016/0038-1098(77)90103-X
  • [9] E.J. Samuelsen, G. Shirane, Phys. Status Solidi 42, 241 (1970), doi: 10.1002/pssb.19700420125
  • [10] S.O. Demokritov, N.M. Kreines, V.I. Kudinov, Sov. Phys. JETP 65, 389 (1987)
  • [11] M.T. Hutchings, J. Phys. C 6, 3143 (1973), doi: 10.1088/0022-3719/6/21/018
  • [12] O. Steinsvoll, Physica Scripta 26, 119 (1982), doi: 10.1088/0031-8949/26/2/011
  • [13] A.W. McReynolds, T. Riste, Phys. Rev. 95, 1161 (1954), doi: 10.1103/PhysRev.95.1161
  • [14] R.J. Birgeneau, L.R. Walker, H.J. Guggenheim, J. Als-Nielsen, G. Shirane, J. Phys. C 8, L328 (1975), doi: 10.1088/0022-3719/8/15/006
  • [15] W.J.L. Buyers, T.M. Holden, E.C. Svensson, R.A. Cowley, R.W.H. Stevenson, Phys. Rev. Lett. 27, 1442 (1971), doi: 10.1103/PhysRevLett.27.1442
  • [16] W.J.L. Buyers, D.E. Pepper, R.J. Elliott, J. Phys. C 5, 2611 (1972), doi: 10.1088/0022-3719/5/18/011
  • [17] U. Köbler, Int. J. Thermodyn. 18, 277 (2015), doi: 10.5541/ijot.5000130678
  • [18] U. Köbler, A. Hoser, J.-U. Hoffmann, Physica B 382, 98 (2006), doi: 10.1016/j.physb.2006.02.007
Document Type
Publication order reference
YADDA identifier
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.