Substrate facet replication by epitaxial magnetic garnet films

Epitaxial ferrimagnetic garnet films were deposited on Czochralski grown single crystal gadolinium gallium garnet substrates containing faceted regions. Films grown by both chemical vapor deposition (CVD) and liquid phase epitaxy (LPE) were studied. Lattice parameter distributions were determined by the method of X-ray double crystal topography with rocking curve analysis. The demagnetized domain strip width, magnetization, and characteristic length were measured in a CVD film in regions inside and outside the substrate facets. It was determined that replication of the substrate facets by the epitaxial film is accomplished by a difference in film stress. This stress difference arises from the lattice parameter difference between the faceted and unfaceted regions of the substrate. These results lead to the establishment of a criterion for allowable lattice parameter variation in substrates to be used for magnetic bubble domain films with stress induced anisotropy.