In Slavov et al., 2010, we can find the Raman spectroscopy used to investigate the magnetite nanoparticles dispersed in two types of β-cyclodextrin suspensions. "The effect of elevating laser power on the structural stability and chemical composition of magnetite in the ferrofluids is discussed. … Powder samples undergo total phase transition from magnetite to hematite at laser power of 1.95 mW. … The Raman spectra revealed that the main phase of the magnetic [particle] core … is magnetite. That is indicated by a strong and non-diminishing in intensity peak at 670 cm -1 " . "A second phase is present at the nanoparticle's surface with Raman spectroscopy unveiling maghemitelike and small fractions of goethite-like structures" .