Magnetization and ferromagnetic resonance studies in implanted and crystalion sliced bismuth-substituted yttrium iron garnet films

Bismuth-substituted yttrium iron garnet (Bi-YIG) is the material of choice in the fabrication of optical isolators. Recently some of us have demonstra ted an ion-implantation based technique for detaching single-crystal Bi-YIG films from their gadolinium gallium garnet growth substrates, and for thei r subsequent bonding onto semiconductor wafers. In this article we study th e magnetic properties of bubble-type Bi-YIG films with large out-of-plane u niaxial anisotropy in various stages of the separation process. We find tha t the implantation reduces the perpendicular anisotropy field from approxim ately 1435 to 750 Oe as a result of increased residual strain. Annealing pa rtially restores the anisotropy to 900 Oe depending on annealing conditions . Chemical etching of the implanted sample separates the Bi-YIG film from t he substrate at the sacrificial layer. Upon detachment the perpendicular an isotropy of the sample is nearly fully restored to its original value. The 9 GHz ferromagnetic resonance (FMR) linewidth of these films is large (440- 520 Oe) and is only weakly affected by the processing. (C) 1999 American In stitute of Physics. [S0021-8979(99)16808-7].