A New Relaxor Ferroelectrics Ba4SrBiTi3Nb7O30 with Tungsten Bronze Structure.

This paper reports the synthesis, microstructure and electrical properties of a new Ba₄SrBiTi₃Nb₇O₃₀ ceramic. X-ray diffraction analysis shows that the sample crystallizes into tungsten bronze structure, and the space group is P4bm. The electrical measurement results show that Ba₄SrBiTi₃Nb₇O₃₀ exhibits good dielectric and ferroelectric properties. The temperature-dependent dielectric permittivity indicates that the transition temperature of the prepared Ba₄SrBiTi₃Nb₇O₃₀ sample is around T_m ≈ 250K. With increasing the frequency, the dielectric peak moves to a lower temperature. Below 250 K, obvious polarization current can be detected, corresponding to the formation of spontaneous ferroelectric polarization. These results indicate the relaxor ferroelectric behavior of Ba₄SrBiTi₃Nb₇O₃₀ ceramic. [ABSTRACT FROM AUTHOR]