Detail investigations of SmFeO 3 under extreme condition

Abstract Temperature and pressure dependent Raman spectroscopic studies are presented which showed signatures of spin-reorientation transition in SmFeO 3 . The x-ray diffraction study as a function of pressure is also presented that shows the variation in structural parameters like inter-atomic distances, bond angles and degree of octahedral tilt. The electron density plots obtained from Rietveld refinement of the high pressure x-ray diffraction provides a direct visualization of the deformation at the Fe-site, while there is more symmetric structure at the Sm site. The variation in the FeO 6 octahedral tilt at high pressures results in large variations in the phonon spectra at the respective pressures indicating modification in local symmetry leading to changes in magnetic structure. The observations in Raman spectroscopy studies are supplemented by density functional theoretical studies. The Raman frequencies calculated from the DFT matched well with the observed values and both showed a subtle modulation between 8 and 12 GPa.