Growth and characterization of rare-earth iron garnet single crystals modified by bismuth and ytterbium substituted for yttrium

A new bismuth-substituted mixed rare-earth iron garnet bulk single crystal of composition (YYbBi)3Fe5O12 (YYbBiIG) has been grown by the improved flux method, whose temperature derivative β of Faraday rotation angle at 45° has been modified by substituting Y3+ and Yb3+ ions in garnet crystals. The Faraday rotation and the optical absorption coefficient of Y1.53Yb0.92Bi0.55Fe5O12 at 1550 nm were found to be −634° cm−1 and 2.56 cm−1, respectively. The Faraday rotation temperature derivative β was 0.01° (°C)−1 at 1550 nm wavelength, the saturation magnetization 4πMs has been estimated to be about 1200 G. The larger Faraday rotation, low optical loss, low saturation magnetization and nearly zero temperature derivative β of Faraday rotation of YYbBiIG crystal promise its use in high-performance magnet-optical applications.