Low temperature Raman and high field 57Fe Mossbauer study of polycrystalline GaFeO3

The magnetic and phonon properties of polycrystalline magnetoelectric/multiferroic GaFeO3 are studied. Using high field Fe-57 Mossbauer spectroscopy, occupation of Fe is observed at four cation sites. A Fe population of about 6% is observed at the tetrahedral Ga1 site, which explains the observed pinched-like M-H curve and initial sharp increase of the magnetization. The calculated net magnetization value from Mossbauer data suggests that the Fe moment at the Ga1 site is parallel to Fe1 and opposite to that of Fe2 and Ga2 sites, resulting in ferrimagnetism. From low temperature Raman data, anomalous temperature variation in frequency at T-C is observed for the mode at similar to 700 cm(-1).