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Crystalline solutions of 0.57(Bi1−xLax)FeO3−0.43PbTiO3 (BLF-PT) for x=0, 0.1, 0.2, and 0.3 have been fabricated by the solid state reaction method. The dielectric constant of BLF-PT was significantly enhanced by using La substitutions, reaching about 1850 for x=0.3. The ferroelectric-paraelectric phase transition of BLF-PT becomes more diffused with a decreased transition temperature for higher La concentration. BLF-PT of x=0.2 exhibits multiferroic characteristics with the simultaneously enhanced remnant magnetization and polarization of 0.119 emu/g and 33.5 μC/cm2, respectively.

Silver in the form of AgNO 3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method. The effects of AgNO 3 on both the microstructure and electrical properties of the varistors were studied in detail. The optimum addition amount of AgNO 3 in ZnO-based varistors was also determined. The mechanism for grain growth inhibition by silver doping was also proposed. The results indicate that the varistor threshold voltage increases substantially along with the AgNO 3 content increasing from 0 to 1.5mol%. Also, the introduction of AgNO 3 can depress the mean grain size of ZnO, which is mainly responsible for the threshold voltage. Furthermore, the addition of AgNO 3 results in a slight decrease of donor density and a more severe fall in the density of interface states, which cause a decline in barrier height and an increase in the depletion layer.

(1-x)(Bi(0.9)La(0.1))FeO(3-x)PbTiO(3) (BLF-PT) crystalline solutions for x = 0.35, 0.37, 0.4, 0.43 and 0.45 have been prepared by the solid-state reaction method. The X-ray diffraction analysis shows that BLF-PT has a single perovskite phase with mixed tetragonal and rhombohedral phases between x = 0.4 and 0.43. The Curie temperature of BLF-PT for x = 0.4 attains 460 degrees C, which is about 80 degrees C higher than that of hard Pb(Zr,Ti)O(3) ceramics. The remnant polarization and piezoelectric constant of BLF-PT for x = 0.4 reach 38 microC/cm(2) and 112 pC/N, respectively. The planar coupling factor k(p) of BLF-PT for x = 0.4 remains stable at temperature increases of up to 360 degrees C. The impedance spectroscopy study reveals that the high temperature conduction of BLF-PT may be attributed to the motion of oxygen vacancies within the material. Our results indicate that BLF-PT is a promising candidate for high temperature applications.

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