Laser annealing of magneto-optic garnet films: Localized control of direction of magnetization

A laser annealing technique has been developed for local modification of the magnetic anisotropy in LPE-grown iron garnet films. Localized annealing was done with a cw argon laser beam by heating the film preheated at
800 \sim 1100 \deg
C in an infrared-furnace. By controlling the furnace temperature, laser power and irradiation time, the direction of the magnetization is changed with no damage to the film. Wide margin and good reproducibility are obtained. The film thickness, refractive index, optical absorption loss and film-substrate lattice misfit are not changed by laser annealing. Interdiffusion of atoms at the film-substrate interface may be negligible.