Raman microspectroscopy of some iron oxides and oxyhydroxides

TLDR

Iron oxides and oxyhydroxides such as hematite, magnetite, wüstite, maghemite, goethite, lepidocrocite, and δ‑FeOOH have been studied by Raman spectroscopy, yet reported data show disagreements. This study aimed to examine how laser power influences the Raman spectra of these iron compounds. Raman microscopy was performed with low laser power for reference spectra to reduce degradation, then higher powers were applied to assess changes. Increasing laser power caused hematite’s characteristic bands to appear in most spectra, while the hematite spectrum itself broadened and shifted. © 1997 John Wiley & Sons, Ltd.

Abstract

Hematite (α-Fe2O3), magnetite (Fe3O4), wüstite (FeO), maghemite (γ-Fe2O3), goethite (α-FeOOH), lepidocrocite (γ-FeOOH) and δ-FeOOH were studied by Raman microscopy. Such compounds have already been studied by Raman spectroscopy, but there are some disagreements in the reported data. Here, Raman microscopy was employed to investigate the laser power dependence of the spectra of these oxides and oxyhydroxides. Low laser power was used for the reference spectra in order to minimize the risks of spectral changes due to sample degradation. The results obtained show that increasing laser power causes the characteristic bands of hematite to show up in the spectra of most of the compounds studied whereas the hematite spectrum undergoes band broadening and band shifts. © 1997 John Wiley & Sons, Ltd.