Bi-Substituted LPE Garnet Films with FMR Linewidth as Small as YIG

Highly Bi-substituted LPE garnet films, Bi_0.85Lu_2.15Fe₅O₁₂ and Bi_1.4Y_1.6Fe₅O₁₂, with FMR linewidths as small as that of YIG, have been grown using only Bi₂O₃ as a flux. Substitution of Al for Fe causes a sharp increase in ΔH. The minimum values of ΔH obtained were 1.5 Oe for Bi_0.85 Lu_2.15 Fe₅ O₁₂ films and 0.73 Oe for Bi_1.4 Y_1.6Fe₅O₁₂ films, which are the smallest values reported to date for such heavily Bi-substituted garnet films. This may be ascribed to the fact that no Pb was included in the films. It was experimentally verified that MSSW propagation is possible for Bi_0.85Lu_2.15Fe₅O₁₂ films. These films are very promising for MSW-based optical waveguide devices, since they have a specific Faraday rotation ten times larger than that of YIG, as well as a very small optical absorption coefficient at a wavelength of 1.3 /spl um/m.