High dielectric constant and low-loss dielectric ceramics of Sr₅LnTi₃Ta₇O₃₀ (Ln=La, Nd, Sm and Y)

Abstract

Polycrystalline Sr₅LnTi₃Ta₇O₃₀ (Ln=La, Nd, Sm and Y) ceramics were prepared as single-phase materials through conventional solid-state ceramics method. The structure was characterized by X-ray diffraction method and scanning electron microscopy (SEM). The dielectric properties were measured from room temperature to 400 °C. All compounds are paraelectric phases adopting the filled tetragonal tungsten bronze (TB) structure at room temperature. At 1 MHz their dielectric constant (ε _r) varied from 109 to 139, dielectric loss changed from 0.003 3 to 0.005 8, and the temperature coefficients of the dielectric constant (τ _ε) moved from −710 to −880×10⁻⁶ °C⁻¹.

Keywords

dielectric properties / paraelectric / tungsten bronze / tantalates

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