Bi-substituted iron garnet films exhibiting stable Faraday rotation against wavelength variation in the 1.55 μm band

We found a Bi-substituted iron garnet film (Tb/sub 1.86/Bi/sub 1.14/Fe/sub 4.67/Al/sub 0.24/Co/sub 0.09/O/sub 12/) which was characterized by stable Faraday rotation against wavelength variation in the 1.55 /spl mu/m band. First, Co- and Bi-substituted iron garnet films were grown by liquid phase epitaxy (LPE), and the dependence of their Faraday rotation against wavelength variation was measured. It was found that the dependence of Bi-substituted iron garnet films on wavelength was reduced in the 1.55 /spl mu/m band due to a Faraday rotation attributable to Co/sup 3+/ ions. Faraday rotation-wavelength coefficients (FWC) of these films in the 1.53 /spl mu/m-1.57 /spl mu/m band were 0.01%/nm, or virtually zero. Also relations between FWC and film composition were discussed.