Bi-substituted iron garnet films for one-dimensional magneto-photonic crystals: Synthesis and properties

Graphical abstract: Faraday hysteresis loops for Bi1.0Y0.5Gd1.5Fe4.2Al0.8O12 film on glass-ceramic substrate (a), Bi2.8Y0.2Fe5O12 film on gallium–gadolinium garnet (b) and for glass-ceramic/SiO2/Bi1.0Y0.5Gd1.5Fe4.2Al0.8O12/Bi2.8Y0.2Fe5O12 structure (c). Highlights: ► Bismuth-substituted iron garnet films as magneto-optical layers in magneto-photonic crystals. ► It is impossible to crystallize the films with high Bi content on amorphous substrates. ► The crystallization of the films can be achieved by their deposition on buffer layer with low bismuth content. -- Abstract: The crystallization processes in Bi2.8Y0.2Fe5O12, Bi2.5Gd0.5Fe3.8Al1.2O12, Bi1.5Gd1.5Fe4.5Al0.5O12 and Bi1.0Y0.5Gd1.5Fe4.2Al0.8O12 garnet films deposited by reactive ion beam sputtering on (1 1 1) gadolinium–gallium garnet substrates, optical glass-ceramic and SiO2 films have been studied. Films were annealed at low pressure in oxygen atmosphere and in the air. The possibility of preparation of crystalline garnet films with high concentration of bismuth on the SiO2 films using a buffer layer with low concentration of Bi has been shown. This allows to produce one-dimensional magneto-photonic crystals with high effective Faraday rotation (several tens of°/μm for the visible optical spectrum).