Dielectric Properties of Ba4Sm2Fe2M8O30 (M=Nb, Ta) with Tetragonal Bronze Structure

The tetragonal tungsten bronze (TTB)‐structured Ba4Sm2Fe2M8O30 (M=Nb, Ta) dielectrics were prepared and investigated. Dielectric and ferroelectric behaviors revealed that the niobate and the tantalate display ferroelectric and paraelectric nature at room temperature (RT), respectively. The dielectric spectrum showed that Ba4Sm2Fe2Ta8O30 ceramic has a high dielectric constant (∼97), a comparatively low temperature coefficient of dielectric constant (∼−105 ppm/°C), and a low dielectric loss (∼10−3) (at 1 MHz). These results indicated that the present tantalate might be a new temperature‐compensating ceramic.