Ba ₄ Ln ₂ Fe ₂ Ta ₈ O ₃₀ (Ln=Pr, Eu): Temperature‐Stable Low Loss Dielectrics with a Tungsten Bronze Structure

Abstract

The dielectric ceramics Ba 4 Pr 2 Fe 2 Ta 8 O 30 and Ba 4 Eu 2 Fe 2 Ta 8 O 30 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 (τ ɛ ) of −30 and −63 ppm/°C, with a high dielectric constant (ɛ r ) of 110 and 87.6 together with a low dielectric loss (tan δ) of 0.0010 and 0.0012 (at 1 MHz) for Ba 4 Pr 2 Fe 2 Ta 8 O 30 and Ba 4 Eu 2 Fe 2 Ta 8 O 30 , respectively. These results indicated that the Ba 4 Ln 2 Fe 2 Ta 8 O 30 (Ln=Pr, Eu) ceramics might be promising in temperature‐stable multilayer ceramic capacitors.