High-throughput characterization of Bi_xY_(3-x)Fe_5O_(12) combinatorial thin films by magneto-optical imaging technique

摘要

Bi_xY_(3-x)Fe_5O_(12) thin films have been grown on GGG (Gd_3Ga_5O_(12)) (111) substrates by the combinatorial composition-spread techniques under substrate temperature (T_(sub)) ranging from 410 to 700℃ and O_2 pressure of 200 mTorr. In order to study the effect of substrates on the deposition of Bi_xY_(3-x)Fe_5O_(12) thin films, garnet substrates annealed at 1300℃ for 3 h were also used. Magneto-optical properties were characterized by our home-designed magneto-optical imaging system. From the maps of Faraday rotation angle θ_F, it was evident that the Faraday effect appears only when T_(sub) = 430-630℃. θ_F reaches to the maximum value (～6°/μm, λ = 632 nm) at 500℃, and is proportional to the Bi contents. XRD and EPMA analyses showed that Bi ions are easier to substitute for Y sites and better crystallinity is obtained for annealed substrates than for commercial ones.