Far-infrared reflection and ellipsometry measurements on multiferroic PrFe3(BO3)4 and SmFe3(BO3)4 single crystals were used to investigate the interaction between lattice phonons and electronic excitations associated with 4f crystal-field transitions. A temperature-dependent interference between two types of excitations was observed in PrFe3(BO3)4 in which the frequency of 4f crystal-field electronic excitation of Pr3+ falls into the TO-LO frequency interval of the optical phonon mode near 50 cm-1 (1.5 THz). Experimental data were explained on the basis of a theoretical model of coupled electron-phonon modes. The fitting procedure revealed the value 14.8 cm-1 for the electron-phonon coupling constant. This rather large value points to an essential role played by the electron-phonon interaction in the physics of multiferroics.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Sep 2 2014|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics