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Raman scattering studies of spin‐waves in hexagonal BaFe 12 O 19
Author(s) -
Hien Nguyen Thi Minh,
Han Kiok,
Chen XiangBai,
Sur Jung Chul,
Yang InSang
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4100
Subject(s) - raman spectroscopy , phonon , condensed matter physics , spin (aerodynamics) , raman scattering , spin wave , hexagonal crystal system , crystal (programming language) , wavenumber , scattering , crystallography , crystal structure , atmospheric temperature range , materials science , chemistry , physics , optics , ferromagnetism , programming language , meteorology , computer science , thermodynamics
We present the results of polarized Raman spectroscopy of hexagonal BaFe 12 O 19 single crystal. The spectra, recorded from 200 to 800 cm –1 and 1100 to 1700 cm –1 in the 20–250 K temperature range, are analyzed on the basis of both crystal vibrations and spin‐waves. In the low wavenumber range, the Γ‐point phonons are observed. In the high wavenumber range, phonon mixings are observed; more interestingly, four modes of spin‐waves are identified in hexagonal BaFe 12 O 19 . Both have not been studied previously. Our analyses of the spin‐waves provide an optical method for quantitatively estimating the spin exchange interactions in hexagonal BaFe 12 O 19 . The four strong exchange integrals are found to have the values of J ce = 1.31 meV, J ae = 1.36 meV, J cd = 1.46 meV, and J bd = 1.71 meV. Our results also indicate that at ~200 and ~80 K, there would be additional spin‐ordering transitions in hexagonal BaFe 12 O 19 . Copyright © 2012 John Wiley & Sons, Ltd.