Dielectric Properties of Ba 4 Sm 2 Fe 2 M 8 O 30 (M=Nb, Ta) with Tetragonal Bronze Structure

The tetragonal tungsten bronze (TTB)‐structured Ba 4 Sm 2 Fe 2 M 8 O 30 (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 Ba 4 Sm 2 Fe 2 Ta 8 O 30 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.