Laser annealing of calcium-doped yttrium iron garnet films in a controlled atmosphere

The Fe4+ ion population of calcium-doped yttrium iron garnet films can be significantly increased or decreased by laser annealing in controlled (oxidizing or reducing) atmospheres. Such changes in the Fe4+ ion population markedly affect the optical and electrical properties of this material. This process is much faster than conventional furnace annealing and allows local small-scale maskless treatments which are of obvious interest for device applications. The feasibility of "writing" bright (highly resistive) lines on dark (low resistivity) backgrounds and vice versa by means of a laser beam is demonstrated.