Excitations magnons

Strong-force interaction (nuclear scattering) Magnetic interaction Position of nuclei in solid (lattice structure) Position and orientation of electronic magnetic moments in solids (ferromagnetism, antiferromagnetism) Lattice vibrations (phonons) Spin excitations (magnons, spin waves)... 

Plenary 5. Manuel Cardona, e-mail address cardona .cardix.mpi-stuttgart.de (RS). Studies of high superconductors. These offer all possible Raman transitions—phonons, magnons, free carrier excitations, pair... 

Melnikov, A. V., Radu, I., Bovensiepen, U., Krupin, O., Starke, K., Matthias, F. and Wolf M. (2003) Coherent optical phonons and parametrically coupled magnons induced by femtosecond laser excitation of the Gd(OOOl) surface. Phys. Rev. Lett., 91, 227403. 

The use of lasers for the excitation of Raman spectra of solids has led to the detection of many new elementary excitations of crystals and to the observation of nonlinear effects. In this review we have tried to lead the reader to a basic understanding of these elementary excitations or quasi-particles, namely, phonons, polaritons, plasmons, plasmaritons, Landau levels, and magnons. Particular emphasis was placed upon linear and stimulated Raman scattering at polaritons, because the authors are most familiar with this part of the field and because it facilitates understanding of the other quasi-particles. 

The low energy excitation is observed at finite frequencies only for T In moderate magnetic fields its frequency is increasing as shown in Fig. 2d). Such a shift of the low temperature mode and the order parameter-like dependence on temperature has been taken as evidence that the mode cannot be related to a singlet state and must be identified as a longitudinal magnon [33, 34],... 

Key words Raman scattering, stripe ordering, phonon and two-magnon excitations... 

These results show evidence for not simple two-magnon nature of the band at -730 cm"1. Perhaps possible effects connected with the interaction between spin excitations and collective motion of charge domain-walls21,37 are necessary to be taken into account. 

The broken symmetry of the SDW ground state characterized by a magnetic modulation at wave vector Q in (TMTSF)2X, X = PF6, N03, and so on, is responsible for the activated behavior of the conductivity through the single-particle gap 2A. However, two kinds of collective excitations arise in the SDW condensate. They are, first, the magnon exci-... 

Regarding both vibrational (phonon) and magnetic (magnon) excitations, the finite particle size imposes an upper wavelength limit. This can be detected in measurements that probe the excitation spectra up to large wavelengths (e.g., inelastic neutron scattering) and it affects the thermodynamic properties of the nanoparticles. 

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