Epitaxial layer-bearing wafer of rare earth gallium garnet for MSW device

Abstract

An improved epitaxial single crystal wafer suitable as a working element of magnetostatic wave devices is proposed which comprises a substrate single crystal wafer of a rare earth gallium garnet, e.g., gadolinium gallium garnet, neodymium gallium garnet and samarium gallium garnet, and an epitaxial layer formed thereon having a chemical composition, different from conventional yttrium iron garnet, Y.sub.3 Fe.sub.5 O.sub.12, of the formula (Y.sub.1-x M.sub.x).sub.a Fe.sub.8-a O.sub.12 or (Y.sub.1-x M.sub.x).sub.a (Fe.sub.1-Y Q.sub.y).sub.8-a O.sub.12, in which M is an element selected from the group consisting of bismuth, lanthanum, gadolinium and lutetium, the subscript a is a positive number in the range from 3.0 to 3.1, the subscript x is a positive number in the range from 0.01 to 0.9, Q is an element selected from the group consisting of aluminum, gallium, indium and scandium and the subscript y is a positive number in the range from 0.1 to 0.2. These epitaxial wafers are advantageous in respect of the greatly decreased problem of mismatching in the lattice constants between the substrate and the epitaxial layer.

Dependencies are inferred from the claim text.