Non-stoichiometry and magneto-optic properties of magnetic bubble thin films of TmIG substituted with bismuth and gallium

Thulium iron garnet thin films substituted with bismuth and gallium were prepared by LPE from a PbO.B₂O₃ flux. Radioactive isotope tracers were added to the melt as the chemical analysis technique. The deviation from the ratio (Pb+Bi+Tm)/(Fe+Ga)=0.6 of the layers was large and a proportion of the thulium ions possibly lie on the octahedral crystallographic sites. The concentration of Bi, Pb, and Ga as a function of the growth temperature was studied. The magneto-optic properties show that the layers are well suited for use in a magneto-optic device. A figure of merit of 2.5 degree per decibel at λ=560 nm was obtained and some magnetic bubble parameters are also presented.