Red shift of Faraday rotation in thin films of completely bismuth-substituted iron garnet Bi3Fe5O12

The magnetooptical Faraday rotations of epitaxial films of BixY3-xFe5O12 (B i:YIG) grown on [111]-oriented gadolinium gallium garnet (GGG) substrates b y pulsed laser deposition (PLD) were studied with bismuth content x = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0. The Faraday rotation angles, theta(F), of the films were measured by the method of rotating analyzer ellipsometry (RAE) w ith the photon energy varied from 1.5 to 3.5 eV. It was shown that in addit ion to the increase of the Faraday rotation with increasing x, the peaks of BF shifted toward the red region as x changed from 1.0 to 1.5. The peak po sitions of theta(F) for the completely Bi-substituted iron garnet, Bi3Fe5O1 2 (BIG), were found at 2.4 and 2.8 eV with peak values as large as -23 deg/ mu m and 44 deg/mu m, respectively.