Red Shift of Faraday Rotation in Thin Films of Completely Bismuth-Substituted Iron Garnet Bi₃Fe₅O₁₂

Abstract

The magnetooptical Faraday rotations of epitaxial films of Bi x Y 3- x Fe 5 O 12 (Bi:YIG) grown on [111]-oriented gadolinium gallium garnet (GGG) substrates by 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, θ F , of the films were measured by the method of rotating analyzer ellipsometry (RAE) with the photon energy varied from 1.5 to 3.5 eV. It was shown that in addition to the increase of the Faraday rotation with increasing x , the peaks of θ F shifted toward the red region as x changed from 1.0 to 1.5. The peak positions of θ F for the completely Bi-substituted iron garnet, Bi 3 Fe 5 O 12 (BIG), were found at 2.4 and 2.8 eV with peak values as large as -23 deg/µm and 44 deg/µm, respectively