Dielectric and relaxor ferroelectric properties of Sr4CaLaTi3Nb7O30 tetragonal tungsten bronze ceramics

Relaxor ferroelectric Sr4CaLaTi3Nb7O30 ceramics were prepared by using the conventional solid state reaction technique. Dielectric property and ferroelectric transition were studied in detail over a broad temperature range. X-ray diffraction analysis revealed that the Sr4CaLaTi3Nb7O30 ceramics crystallizes in the tetragonal tungsten bronze structure with space group P4bm. The dielectric studies confirmed two relaxation regions due to the formation of the polar nanoregions below the deviation temperature similar to 405 K. Relaxations I and II were attributed possibly due to the relaxational contributions from dipole reversal of polar nanoregions and fluctuation of polar nanoregion boundaries, respectively. A maximum dielectric constant of 1177 was found at a measuring frequency of 500 Hz. Room temperature polarization electric field (P-E) hysteresis loops were assessed and a remnant polarization of 0.65 mu C/cm(2) with a coercive field of 3.33 kV/cm was observed under an applied electric field of 58 kV/cm. The Sr4CaLaTi3Nb7O30 ceramics exhibited a prominent dielectric and ferroelectric performance which indicates the potential application of this material in various electronic devices. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.