Dielectric and relaxor ferroelectric properties of Sr4CaLaTi3Nb7O30 tetragonal tungsten bronze ceramics

Abstract Relaxor ferroelectric Sr 4 CaLaTi 3 Nb 7 O 30 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 Sr 4 CaLaTi 3 Nb 7 O 30 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 ~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 μC/cm 2 with a coercive field of 3.33 kV/cm was observed under an applied electric field of 58 kV/cm. The Sr 4 CaLaTi 3 Nb 7 O 30 ceramics exhibited a prominent dielectric and ferroelectric performance which indicates the potential application of this material in various electronic devices.