Raman scattering studies of hexagonal rare‐earth RMnO3 (R = Tb,Dy, Ho,Er) thin films |
| |
Authors: | Nguyen Thi Minh Hien Su‐Young Oh Xiang‐Bai Chen D Lee S‐Y Jang T W Noh In‐Sang Yang |
| |
Abstract: | We have studied the rare‐earth (R) dependence of the phonon and magnon scattering in hexagonal RMnO3 (R = Tb, Dy, Ho, Er) thin films using Raman scattering spectroscopy. We found, as the ionic radius of R decreases from Tb to Er, the phonons shift to higher energies. Our results indicate that both the lattice constants a and c of hexagonal RMnO3 would decrease when the ionic radius of R decreases, and the lattice constant c would have a weaker R dependence. The magnons also shift to higher energies when the radius of the R ion decreases, and they show faster upshift than the phonons. In addition, the Néel temperature also shows a systematic increasing behavior when the radius of the R ion decreases. The dependence of the rare‐earth R on the magnons and the Néel temperature can be explained by the rapid increase of the spin‐exchange integral when the Mn–Mn distance decreases. Copyright © 2011 John Wiley & Sons, Ltd. |
| |
Keywords: | hexagonal RMnO3 phonon scattering magnon scattering spin‐exchange integral Né el temperature |
|
|