Dielectric and Ferroelectric Characteristics of BaNdFeNbO Tungsten Bronze Ceramics Rapid Communications of the American Ceramic Society.

Ba5NdFe1.5Nb8.5O30 tungsten bronze ceramics were prepared, and the dielectric and ferroelectric characteristics were evaluated together with the structure. The filled tungsten bronze structure in space group P4bm was confirmed. Two obvious dielectric relaxations were observed in the temperature range from 163 to 623 K, and there was a dielectric constant plateau with weak temperature dependence between them. A Debye-type dielectric relaxation in temperature range from 163 to 410 K is identified to originate from combination effect of the reorientation of the off-center Fe/Nb ions coupling with charge carrier hopping. The high-temperature (550-623 K) relaxation can be attributed to the Maxwell-Wagner effects. Moreover, another weak dielectric relaxation was determined below 200 K. The present ceramics exhibited room-temperature ferroelectric property with Pr=1.0 μC/cm². [ABSTRACT FROM AUTHOR]