Bubble properties of garnet films prepared from molybdate fluxes

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Abstract
Magnetic bubble garnet films have been prepared from a flux composed of lithium and rare earth molybdates using liquid phase epitaxial techniques. In general, the quality and magnetic properties of 〈111〉 films prepared on GGG substrates compare favorably with the properties of similar garnets prepared from PbO based fluxes. A notable exception, however, is a persistent, unusually low value of the growth induced anisotropy (Ku). Typically, Y3−xEuxFe5−yGayO12 films grown at ∼950 °C containing as much as Eu=0.6 and Ga=0.9 have a moment (4πMs) ?400 G and Ku?103 ergs/cm3 when grown from the molybdate flux. Films prepared on 〈100〉 substrates exhibit comparably low Ku values and K1 values of ∼−2.3×103 ergs/cm3. As these films are virtually contaminant free with regard to the flux components, and PbO and B2O3 additions have essentially no effect on Ku, our present understanding of the nonrandom rare earth ion distribution responsible for growth induced anisotropy in garnets may not be adequate to explain these data. Other anomalies which have been observed in these films and will be discussed are the occurrence of triangular bubble domains and square lattice bubble arrays.