Abstract :
Phonon dynamics was investigated on Y Mn1−xFexO3( 0 ≤ x ≤ 0.20 ) hexagonal manganite polycrystals. Phonon modes were properly assigned using results obtained on Y MnO3 single crystal, by mixing the a b 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.
