Ultra-high dielectric constant garnet

A synthetic garnet material comprising a yttrium iron garnet crystal structure with bismuth being substituted for at least some yttrium; titanium, strontium, hafnium, indium, ytterbium, lanthanum, praseodymium, neodymium, samarium, dysprosium of holmium being substituted for at least some yttrium; and charge balance achieved by calcium and/or zirconium substituting for at least some yttrium. Preferably, both Ca and Zr are used to achieve charge balance. Preferably, the synthetic garnet material does not comprise yttrium. The material used may be free of sillenite. Also claimed is a method of manufacturing a synthetic garnet material comprising providing a YIG crystal structure, substituting bismuth for at least some yttrium, substituting one of Ti, Sr, Hf, In, Yb, La, Pr, Nd, Sm, Dy, Ho for yttrium and charge balancing by substituting Ca and/or Zr for Y.