Ba_4Ln_2Fe_2Ta_8O_(30) (Ln = Pr, Eu): Temperature-Stable Low Loss Dielectrics with a Tungsten Bronze Structure

摘要

The dielectric ceramics Ba_4Pr_2Fe_2Ta_8O_(30) and Ba_4Eu_2Fe_2 Ta_8O_(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_ε) of -30 and -63 ppm/ ℃, with a high dielectric constant (ε_r) of 110 and 87.6 together with a low dielectric loss (tan 8) of 0.0010 and 0.0012 (at 1 MHz) for Ba_4Pr_2Fe_2Ta_8O_(30) and Ba_4Eu_2Fe_2Ta_8O_(30), respectively. These results indicated that the Ba_4Ln_2Fe_2Ta_8O_(30) (Ln = Pr, Eu) ceramics might be promising in temperature-stable multilayer ceramic capacitors.