Raman spectra of superconductor NdFeAsO1-x Fx (x=0.0,0.1,0.2) compounds have been systematically investigated as functions of temperature and fluorine concentration. It was found that fluorine doping leads to structure disorder of insulator Nd-O layers and detectable downshift as well as increased temperature coefficients of the Fe-As vibrational modes. Additionally, low-temperature Raman measurements reveal that the in-plane phonon modes of the layered compound are unusually more sensitive to temperature change than those along the axis, and this anisotropic temperature dependence of phonon models is further enhanced by fluorine doping.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2009 Feb 26|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics