PREPARATION OF GARNET FILMS FOR MAGNETIC BUBBLE DEVICES.

The preparation of high quality 30 mm diameter Y//2//. //6Sm//0//. //4Ga//1//. //2Fe//3//. //8O//1//2 films for magnetic buble devices is discussed. This includes the techinques for eliminating magnetic defects in wafers, for achieving uniform magnetic properties in a wafer and for successively growing films with identical magnetic properties by liquid phase epitaxy. Magnetic defects could be eliminated by using carefully cleaned Gd//3Ga//5O//1//2 single crystal substrates free from dislocation, core and scratch, and by selecting an optimum molar ratio of melt composition in the epitaxial growth. Not only film thickness uniformity but also magnetic properties uniformity were achieved by selecting an adequate substrate rotation speed. A 65% yield of wafer, controlled within plus or minus 1% in magnetic properties was achieved by a large volume melt of 2500 g.