High dielectric constant and low-loss dielectric ceramics of Ba5LnZnNb9O30 (Ln = La, Nd and Sm)

Polycrystalline Ba5LnZnNb9O30 (Ln = La, Nd and Sm) ceramics were prepared as single-phase materials through conventional solid-state ceramics route. The structure was characterized by X-ray diffraction methods and scanning electron microscopy (SEM) and the dielectric properties were measured from − 120 °C to 150 °C. All three compounds are paraelectric phases adopting the filled tetragonal tungsten–bronze (TB) structure at room temperature, and the Curie temperature (at 1 MHz) were − 60, − 25 and − 5 °C for Ba5LaZnNb9O30, Ba5NdZnNb9O30, and Ba5SmZnNb9O30 respectively. At 1 MHz their dielectric constant (εr) varies from 258 to 310, dielectric loss (tanδ) from 0.0033 to 0.0068, and the temperature coefficients of the dielectric constant (τε) from − 1220 to − 1390 ppm °C− 1.