Phonon dynamics of hexagonal YMn1-xFexO3

Phonon dynamics was investigated on YMn1-xFexO3(0 <= x <= 0.20) hexagonal manganite polycrystals. Phonon modes were properly assigned using results obtained on YMnO3 single crystal, by mixing the ab plane and the c axis optical responses. Upon increasing the Fe content, most of the phonon mode frequencies do not vary drastically. However, some modes involving Y and O atom displacements along the c axis are affected by doping. Indeed, a redshift of their transverse optical frequency was interpreted as an elongation of Y-O distance along the c-axis, resulting in a change in yttrium coordination. (C) 2011 Elsevier Ltd. All rights reserved.