The origin of the uniaxial anisotropy in thin films of (YLaPb)3 (FeGa)5O12 and its variation along the growth direction

The uniaxial anisotropy of La, Ga: YIG films grown by liquid phase epitaxy has been measured using spin-wave resonance techniques. The results show that in films produced at growth temperatures above 840°C on [111] Gd₃Ga₅O₁₂ substrates the uniaxial anisotropy is stress induced. At lower growth temperatures the Pb incorporation gives rise to a positive growth-induced anisotropy of 4×10⁴ erg/cm³ per Pb atom per formula unit. Around the growth temperature of 840°C, where the Pb and La effects cancel, homogeneous films can be grown. Variations of anisotropy within the filmsthickness will be shown to be due to variations of local growth rates which in turn cause composition changes.