Determination of the complex refractive index of nanoparticulate magnetite from optical anisotropy data for magnetic colloids

Abstract

Spectral dependences of birefringence and dichroism in magnetic colloids of magnetite nanoparticles have been studied. The results demonstrate that previously reported spectra of the refractive index of bulk magnetite are poorly suited for quantitative and qualitative interpretation of optical effects in magnetic fluids. Data on magneto-optical effects in magnetic colloids have been used to determine spectra of the real and imaginary parts of the refractive index of nanoparticulate magnetite in the wavelength range 400–1050 nm.