Bismuth substituted iron garnet thin films deposited on silicon by laser ablation

Thin films of bismuth substituted iron garnet are fabricated on silicon (100) substrates using the pulsed laser deposition technique. There is a narrow temperature range in which good polycrystalline garnet films can be grown on silicon; it must be higher than 575 °C for the films to crystallize and lower than 700 °C to avoid chemical reaction between the silicon substrate and the deposited materials. Film microstructure and magnetic properties are compared for films grown at different growth conditions and annealing procedures. The films heated during deposition are smooth and dense in contrast to the post-annealed films, which are characterized by clusters of many smaller grains separated by large cracks and a very small coercivity.