Magneto-optical properties and gyration vectors of iron garnet films containing different bismuth ions

Iron garnet is a material with a good Faraday effect, especially in the visible and infrared wavelengths, and it has been found that the magneto-optical effect of this material can be enhanced by the introduction of Bi3+ ions. In this work, the effect of the gyration vector in the dielectric constant on the refractive index is investigated by fitting the equation of the gyration vector in the dielectric constant of BixY3-xFe5O12 based on that the gyration vector of iron garnet films is proportional to the magnetization intensity. After comparing the gyration vector formulation of BixY3-xFe5O12, the Faraday effect and transmittance of the film with a thickness of 200 nm were calculated numerically, and the results showed that Bi3Fe5O12 has a better strengthening effect than Y3Fe5O12. The authors analyzed the Faraday rotation angle and transmittance with different thicknesses of Bi3Fe5O12 and also investigated the effect of the applied magnetic field on the Faraday rotation angle, reaching -58° at a magnetic field of 1.5 T. Compared with the model with surface metal structure, the magneto-optical film studied in this paper has the advantages of easy preparation and large Faraday rotation angle, and provides a new idea for the development of magneto-optical devices.