Abstract
Ferrimagnetic insulating yttrium iron garnet (YIG) are widely used in microwave devices due to their unique magnetic, electrical and microwave properties. The substitution of rare earth ion for the Y^3+ ion can modulate or improve its high-frequency properties for microwave application. We prepared a serial of single-phased polycrystalline Y3-xGdxFe5O12 garnet samples with x = -- 3.0 by the conventional ceramic technique. The refinement of X-ray diffraction patterns of the samples shows them to crystallize in a centrosymmetrically cubic structure with a Ia3d space group. Both the lattice constant and dc saturation magnetization at room temperature decrease with increasing Gd^3+ We also measured the low- and high-frequency dielectric constant and tangent loss. As well, the spin wave line width δHk regarding the ferromagnetic resonance behavior is on progress. These results are important to develop high-power circulators and isolators in microwave range.