Low temperature Faraday rotation spectra of Y3-xBixFe5O12¬

The liquid nitrogen and room temperature Faraday rotation spectra of polycrystalline bismuth substituted yttrium iron garnet Y3-xBixFe5O12, x = 0, 0.24, 0.37, and 0.61, in the spectral range between 0.54 and 2.4 μm are presented. The results are discussed on the basis of the sublattice model. Performed quantitative calculations of magnetooptical coefficients spectra indicate a marked increase of tetrahedral component in Bi-YIG compared to pure YIG. The change in sign and the strong increase in the intensity of the Faraday rotation induced by bismuth substitution can thus be understood as an increase in optical transition intensities of Fe³⁺ions in the tetrahedral sites.