Ion Beam Sputtered Films of Bismuth-Substituted Yttrium Iron Garnet

Compared with the conventional liquid phase epitaxy method (LPE), ion beam sputtering (IBS) has advantages in heavy doping of Bi ions, since it is an essentially nonthermal equilibrium process. IBS was used to prepare Bi-substituted YIG films. Epitaxial growth along the {111} direction was observed, however, and small amounts of polycrystalline garnet phase were also found. Bi content of the films reached 2.75/(formula unit). Investigation of the dependences of Faraday rotation on Bi content of the films and on the target composition showed that Faraday rotation reached a maximum of -4.3 × 10⁴ deg/cm, as high as that reported for LPE grown films [1]. Slight contamination of the films by the materials of the ion gun, the grids, iris, wall and target holder was detected.