Crystal structure, dielectric, ferroelectric and energy storage properties of La-doped BaTiO3 semiconducting ceramics

Abstract

Polycrystalline La-doped BaTiO 3 (Ba ð1ÀxÞ La x TiO 3 ) [x ¼ 0; 0:0005; 0:001; 0:003] ceramics (denoted as BTO,BLT1,BLT2,BLT3) were synthesized by conventional solid-state reaction method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. XRD and Raman spectra revealed single-phase tetragonal perovskite crystalline structure. Well-saturated polarization-electric field (P-E) hysteresis loops were observed with the measurement frequency of 50 Hz at room temperature and confirmed ferroelectric nature of these ceramics and a high recoverable electrical energy storage density of 0.350 J/cm 3 with energy efficiency ðnÞ $ 9%, which is useful in energy storage capacitor applications. Dielectric studies revealed anomalies around 415-420 K and near the Curie temperature. The latter is attributed to the ferroelectric to paraelectric phase transition. Better dielectric performances were obtained for La-doped samples sintered at 1350 C for 4 h. Grain growth is inhibited with lanthanum (La) incorporation into the BTO lattice. Room temperature semiconducting behavior with positive temperature coefficient of resistivity (PTCR) behavior at T C is attributed to electron compensation mechanism.

Phase coexistence and large piezoelectricity in BaTiO3‐CaSnO3 lead‐free ceramics

“…Figure A displays the Raman spectra of the BTCS‐ x ceramics, while the enlarged spectra at the wave number of 100‐400 cm −1 and the variation in the vibration modes with x are shown in Figure B,C, respectively. As well‐known, the pure BT possesses a perovskite structure at room temperature, and each unit cell contains five atoms . Therefore, for the pure BT, there are 12 kinds of optical vibration mode (3F 1u + 1F 2u ) .…”

“…As well‐known, the pure BT possesses a perovskite structure at room temperature, and each unit cell contains five atoms . Therefore, for the pure BT, there are 12 kinds of optical vibration mode (3F 1u + 1F 2u ) . When the phase structure of the materials transforms to T phase, the F 1u splits into the A 1 and E modes, and F 2u splits into the B 1 and E modes .…”

“…31 Therefore, for the pure BT, there are 12 kinds of optical vibration mode (3F 1u + 1F 2u ). 31 When the phase structure of the materials transforms to T phase, the F 1u splits into the A 1 and E modes, and F 2u splits into the B 1 and E modes. 32 In addition, all A 1 and E modes exhibit Raman and infrared activities, and B 1 mode only shows the Raman activity.…”

La doped barium titanate/polyimide nanocomposites: A study of the effect of La doping and investigation on thermal, mechanical and high dielectric properties

“…The spectrum was measured in the range of wavenumber 4000–400 cm −1 . The formation of perovskite structure of the ceramic nanoparticles was supported by FTIR analysis . No peaks were observed for Lanthanum in the graph.…”

“…Here they reported that the Curie temperature increased with La content in the ceramic. The obtained Curie temperature was in the range of 415–420 K . The electrical properties of the La doped barium titanate ceramics were studied by F. D. Morrison et al .…”