Raman Spectroscopy of Natural Titanomagnetites

Abstract

The Raman spectral patterns of analyzed natural titanomagnetite samples revealed peaks at 670-680 cm^-1, 544-603 cm^-1, 407-495 cm^-1 and 373-392 cm^-1 that correspond to the A_1g, T_2g (2), T_2g (3) and E_g vibrational modes of the spinel Fd3m space group. Previous studies of titanomagnetite Raman spectra patterns have suggested the behavior of these peaks reflect the distribution of Fe²⁺-O, Fe³⁺-O and Ti⁴⁺-O bonds within the titanomagnetite crystal structure. The peak intensities of each vibrational modes are observed to be relative, reflecting the re-distribution of Fe²⁺ and Fe³⁺ in both the tetrahedral and octahedral sites as a function of Ti concentration. Existing titanomagnetite Raman spectroscopy studies are limited to analysis of synthetic titanomagnetite. In this study, Raman spectral patterns from natural titanomagnetite i.e., magnetite-ulvöspinel solid solution samples were analyzed to determine behavior of Raman spectrum peak positions and intensities due to changing content of Ti⁴⁺, Fe²⁺ and Fe³⁺.