• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.3
• /
• pp.1-8
• /
• 2002

In order to study electric properties of (Pb$\_$0.9/La$\_$0.1/)Ti$\_$0.975/O$_3$(PLT (10)) films with varying excess lead concentration (7.5, 10, 12.5, 15 ㏖% excess lead), the PLT films were deposited by sol-gel process. DTA analyses reveal that the crystallization temperature of the precursor powers decreased with increasing amount of excess lead. XRD patterns of PLT reveal pure perovskite structure and the preferred orientation increased with increasing Pb content in the films. With increasing amount of excess P$\_$b/, the relative permittivity ($\xi$$\_$r/) increased and leakage current density at 100 ㎸/cm transformed 4.01$\times$10$\^$-5/, 2.42$\times$10$\^$-6/, 1.27$\times$10$\^$-6/, 1.56$\times$10$\^$-6/A/㎠ respectively. In the results of hysteresis loops measured at 166 kV/cm, the remanent polarization (P$\_$r/) and the coercive field (E$\_$c) are 6.36$\mu$C/cm and 58.7 ㎸/cm, respectively (at 12.5 ㏖% excess P$\_$b/) With increasing amount of excess Pb, the remanent polarization for PLT thin film degraded to about 44%, 27%, 15%, 16% of the initial value after 10$\^$9/ cycles./TEX>) With increasing amount of excess Pb, the remanent polarization for PLT thin film degraded to about 44%, 27%, 15%, 16% of the initial value after $10^{9}$ cycles.

• Journal of the Korean Ceramic Society
• /
• v.22 no.2
• /
• pp.17-24
• /
• 1985

In the composition of $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ the effect of particle size on PbO vaporization were measured, . The initial step of discontinuous vaporization of unreated PbO during the calcining process was depended on the particle size. All additives $La_2O_3Nb_2O_5$ and $Al_2O_3$ inhibited the grain growth of the composition $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ +2wt% excess PbO. The dielectric and piezoelectric properties of the composition $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ were improved by the addition of 2wt% excess PbO and proper additive. The electromechanical planar coupling factor of 0.65 and mechnical quality factor of 390 could be obtained by adding 5wt% $Nb_2O_5$ to the composition 2wt% excess PbO+$Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$.

• Korean Journal of Materials Research
• /
• v.10 no.1
• /
• pp.34-40
• /
• 2000

The $Pb_{0.94}Y_{0.04}[(Zr_{0.6}Sn_{0.4})_{0.915}Ti_{0.085}]O_3$ ceramics which corresponded to the antiferroelectric-ferroelectric phase boundary composition were prepared for digital-type-piezoelectric/electrostrictive device application. Their dielectric, field-induced polarization (P) and strain (X) behaviors were studied with variations in sintering condition and excess PbO content. The orthorhombic structure of specimens was hardly affected either by excess PbO addition or sintering temperature. With increasing excess PbO content, grains tended to be smaller and rounded ones, and the optimum sintering temperature was lowered. Excess PbO addition stabilized the antiferroelectric phase of the specimen effectively, which was confirmed by P-E and X-E analyses. Also the digital-type-strain character was found to be enhanced despite of slight increase in phase transition (AFE-FE) field and electrical resistivity, and decrease in maximum strain. These results were explained in terms of possible lattice defects and domain wall motion.

• Journal of the Korean Ceramic Society
• /
• v.26 no.4
• /
• pp.568-574
• /
• 1989

Effect of PbO addition on sintering and piezoelectric properties at 0.45Pb(Ni1/3Nb2/3)O3-0.40PbTiO3-0.15PbZrO3 composition which is tetragonal phase was investigated. In this composition, Porosity and dielectric constant were increased with excess PbO addition, but Kp and d31 was not changed. These variation of physical properties could be interpreted as composition change of solid grains from tetragonal to MPB region due to amount of PbO-rich liquid changing.

• Journal of the Korean Ceramic Society
• /
• v.34 no.1
• /
• pp.31-36
• /
• 1997

The effects of 0 to 10mol% excess MgO addition on the microstructure and dielectric properties in 30Pb(Mg1/3Nb2/3)O3-20PbTiO3-50Pb(Mg1/2W1/2)O3 ternary system were investigated. Samples were prepared by mixed oxide and precursor methods to compare the role of excess MgO. Excess MgO enhanced grain growth and increased dielectric constant. The dielectric constant and tesmperature dependence of dielectric constant of the sample sintered at 100$0^{\circ}C$ with 5mol% MgO were above 5,000 and +25% to -50% from - 55$^{\circ}C$ to 1$25^{\circ}C$, respectively. For these specimens the phases percent were mainly perovskite and Pb2WO5, which was confirmed by XRD analysis. Also the amount of cubic pyrochlore Pb3Nb4O13 and PbWO4 were de-creased with sintering temperature and MgO addition. BSE image showed the chemical inhomogeneous dis-tribution. Crystal phase formed at each sintering temperature and the chemical inhomogeneous distribution caused the decrease of the temperature dependence of dielectric constant.

• Journal of the Korean Ceramic Society
• /
• v.26 no.5
• /
• pp.712-718
• /
• 1989

PMN ceramics with excess MgO addition in the range of 0 to 70m/o were prepared, and their electrical properties, such as dielectric constant, tan$\delta$, diffuseness coefficient, remanent polarization, coercive field and electrical conductivity were measured. Dielectric constant and remanent polarization increased with up to 5m/o excess MgO and then decreased presumely due to the precipitation of second phase, etc. Electrical conductivity slightly increased with the addition of excess MgO.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.12 no.4
• /
• pp.184-189
• /
• 2002

The electrical and optical properties of $(Pb_{0.91}La_{0.09})(Zr_{0.65}Ti_{0.35})O_3$(PLZT) thin films by MOCVD using ultrasonic spraying were investigated. To compensate the Pb loss by evaporation, 5 and 10 wt% of excess Pb was added to 0.2 M precursor. After deposition of films on ITO-coated glasses in oxygen atmosphere for 30 min, films were heated by in-situ RTA (rapid thermal annealing) method. When the films were heat treated at $600^{\circ}C$, perovskite single phase was obtained. The optical property of the film with 10 wt% excess Pb was excellent showing about 84 % of transmittance near 520 nm. The dielectric constant of the film was about 308 and the leakage current of the film was lower than the Pb excess 0, 5 wt% PLZT thin films.

• Journal of the Korean Ceramic Society
• /
• v.30 no.7
• /
• pp.543-548
• /
• 1993

Stability and formation of Pb(Mg1/3Nb2/3)O3 (PMN) phase synthesized in Li2SO4-Na2SO4 molten salts have been investigated. And powder characteristics of PMN have been studied with a variation of processing parameters such as temperature, time, amount of the salts, and excess PbO. More ratio of Li2SO4 to Na2SO4 influences the percentage of perovskite phase due to the difference of the eutectic point of the salts, but does not influence the powder characteristics. The shape of PMN particles shows faceted morphology with bimodal distribution consisting with large and submicron parts. Particle size of PMN increased greatly with increasing soaking time or amount of salts rather than temperature. The addition of excess PbO resulted in round PMN crystallites without submicron particles. These results are discussed by XRD, SEM and thermal analyses.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2000.04a
• /
• pp.32.2-32.2
• /
• 2000

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.378-380
• /
• 1987