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Raman scattering studies of the magnetic ordering in hexagonal HoMnO 3 thin films
Author(s) -
Minh Hien Nguyen Thi,
Chen XiangBai,
Hoang Luc Huy,
Lee D.,
Jang S.Y.,
Noh T. W.,
Yang InSang
Publication year - 2010
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.2531
Subject(s) - raman spectroscopy , raman scattering , thin film , atmospheric temperature range , condensed matter physics , analytical chemistry (journal) , spectral line , hexagonal crystal system , materials science , néel temperature , laser ablation , chemistry , nuclear magnetic resonance , laser , crystallography , optics , magnetization , magnetic field , nanotechnology , physics , chromatography , quantum mechanics , astronomy , meteorology
We present the results of the temperature dependence of the Raman spectra of hexagonal HoMnO 3 thin films in the 13–300 K temperature range. The films were grown on Pt(111)//Al 2 O 3 (0001) substrates using the laser ablation method. In the HoMnO 3 thin films, we initially observedseveral broad Raman peaks at ∼510, 760, 955, 1120, and 1410 cm −1 . These broad Raman peaks display an anomalous behavior near the magnetic transition temperature, and the intensity difference of the Raman spectra at different temperatures shows several pairs of negative and positive peaks as the temperature is lowered below the Néel temperature. Our analyses indicate that all the broad peaks are correlated with magnetic ordering, and we have assigned the origin of all the broad peaks. Purely on the basis of the Raman analysis, we have deduced the Néel temperature and the spin exchange integrals of HoMnO 3 thin films. We also investigated the effects of the growth condition on the strongest broad peak at ∼760 cm −1 , which is related with pure magnetic ordering. This result indicates that the oxygen defect in the HoMnO 3 sample has negligible effect on magnetic ordering. Copyright © 2009 John Wiley & Sons, Ltd.