Dielectric properties of TiO₂–Nb₂O₅ crystallographic shear structures

The dielectric constants (K) have been measured near ambient temperature for polycrystalline bulk ceramics of the crystallographic shear compounds TiNb₂₄O₆₂, Ti₂Nb₁₀O₂₉, and TiNb₂O₇. These show enhanced K's over Nb₂O₅ and TiO₂, with the 2: 10:29 phase displaying an ambient temperature K of approximately 130. We also report the effects of partial substitution of Nb by Ta. In general, the dielectric constants are enhanced for 5–10% Ta substitution, with the detailed behavior differing for the three phases.