Ba4Ln2Fe2Ta8O30 (Ln=Pr, Eu): Temperature-Stable Low Loss Dielectrics with a Tungsten Bronze Structure

The dielectric ceramics Ba4Pr2Fe2Ta8O30 and Ba4Eu2Fe2Ta8O30 with a tetragonal tungsten bronze structure were synthesized and characterized. Dielectric and ferroelectric behaviors indicated that the ceramics are paraelectric above room temperature. Dielectric measurement showed that the present ceramics have high‐temperature stability, a comparatively low temperature coefficient of dielectric constant (τɛ) of −30 and −63 ppm/°C, with a high dielectric constant (ɛr) of 110 and 87.6 together with a low dielectric loss (tan δ) of 0.0010 and 0.0012 (at 1 MHz) for Ba4Pr2Fe2Ta8O30 and Ba4Eu2Fe2Ta8O30, respectively. These results indicated that the Ba4Ln2Fe2Ta8O30 (Ln=Pr, Eu) ceramics might be promising in temperature‐stable multilayer ceramic capacitors.