Magneto-optical properties of Bi-substituted epitaxial rare-earth iron garnet thick films

Films of (Yb,Tb,Bi)3Fe5O12 show excellent characteristics of the Faraday rotator at the wavelength of 1.3 μm; the rotation is −1800 deg/cm, insertion loss 0.3 dB, isolation 38 dB, and the temperature dependence of the Faraday rotation is 0.060 deg/K at room temperature. The films are grown epitaxially on the (Gd,Ca)3(Ga,Mg,Zr)5O12 substrates, from the melt in the flux PbO/B2O3/Bi2O3. The melt contains rare-earth ions (R=Y,Gd,Er,Dy,Tm,Yb,Lu) as c-site components of rare-earth iron garnets, and Fe and Ga+Al as a- and d-site components. The obtained film thickness is in the range 300–400 μm without appreciable defects on the substrate, with a 2-in. diameter. This technology will lead to the efficient production of the optical isolator used in optical systems.