Crystallization of Bismuth-Substituted Yttrium Iron Garnet under Low-Energy High-Repetition Rate Femtosecond Laser Pulses

Femtosecond laser crystallization of magneto-optical bismuth-substituted yttrium iron garnet (Bi/YIG) from an oxide film synthesized by the metal–organic decomposition method was demonstrated and studied. The maximum of the specific Faraday rotation of Bi/YIG films crystallized by laser pulses and that crystallized by conventional thermal annealing was shown to be 11 deg/μm at 515 nm for both types. In cases where Bi/YIG is a functional layer of a multilayered structure on a substrate, the proposed approach allows us to overcome limitations related to overheating of the structure and the substrate occurring during conventional high-temperature annealing.