Composite structures consisting of YIG and (YSmLuCa)3(FeGe)5O12layers were prepared from two different fluxes. YIG was grown from a lithium and yttrium molybdate flux. (YSmLuCa)3(FeGe)5O12which supports 2.5 &mgr;m bubbles was grown from conventional lead borate flux. The very slow growth rates obtainable from molybdate flux makes it ideal for the deposition of submicron thick YIG layers. YIG grown from this flux was found to contain lithium. The lithium content appears to correlate with the observed magnetic and electrical properties. A technique for measuring submicron thick YIG films is described. The effects of YIG on hard bubble suppression in (YSmLuCa)3(FeGe)5O12is reported.