摘要
Polycrystalline La-doped BaTiO_(3)(Ba_(1-x)La_(x)TiO_(3))[x¼0;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 50Hz at room temperature and confirmed ferroelectric nature of these ceramics and a high recoverable electrical energy storage density of 0.350J/cm^(3) with energy efficiency(n)-9%,which is useful in energy storage capacitor applications.Dielectric studies revealed anomalies around 415–420K 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℃ for 4h.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 TC is attributed to electron compensation mechanism.
基金
This work was supported by the National Science Foundation under grant NSF-EFRI RESTOR#1038272.
