Jong Man Jung

Morphotropic phase boundary in relaxor ferroelectric pb(mg1/3nb2/3)o3 ceramics

Abstract The stability of the perovskite phase was studied as a function of sintering temperature. Dielectric, piezoelectric and pyroelectric properties of relaxor ferroelectric in the (1 – x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 solid solution series have been investigated. An important contribution to the dielectric, pyroelectric and piezoelectric behaviors for the solid solution compositions close to the morphotropic phase boundary between rhombohedral and tetragonal regions existing in the grains of the ceramic were observed. The anomalous dielectric and pyroelectric behaviors are observed at the composition x = 0.275-0.325 mole% PT content in the vicinity of the morphotropic phase boundary.

Dielectric, piezoelectric and pyroelectric properties of Pb(Mg1/3Ta2/3)O3-PbTiO3-BaTiO3 system

Abstract Dielectric, piezoelectric and pyroelectric response of selected compositions from this solid solution system have been investigated as a function of PT and BT content for compositions near the morphotropic phase boundary (PMT-PT). The dielectric constant and loss of poled samples were determined. Pyroelectric coefficient, electromechanical coupling factor and piezoelectric d33 constant were observed on various compositions. The transition temperature and peak temperature of the ceramics decreased gradually with the addition of BT. The addition of BT to the PMT-PT system results in slightly reduced dielectric constant. Further addition of BT could be used to shift the Tc downward without significantly changing the electrical behavior.

Synthesis and Ferroelectric Properties of Ni-Modified 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 Solid Solution System

The correlation between the sintering temperature and ferroelectric properties of Ni-modified 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 ceramics has been investigated. The stability of the perovskite phase was studied as a function of sintering temperature. The influence of NiO addition on the microstructural, dielectric and pyroelectric properties of the ceramics is investigated by varying the additive amounts of NiO and the sintering temperature. The optimum conditions for obtaining samples with improved ferroelectric properties are at a sintering temperature of 1050°C and a sintering time of 2 h by a nominal addition of 0.4 wt% NiO. The dielectric and pyroelectric peak temperatures are nonlinearly shifted to a lower temperature with the addition of small amounts of NiO. The diffuseness of the phase transition is almost constant in dopant content.

Dielectric, pyroelectric and piezoelectric properties of bismuth-modified 0.69PMT–0.31PT ceramics

Abstract The dielectric, pyroelectric and piezoelectric properties of relaxor ferroelectric in the 0.69(Pb(1–3x/2)Bix)(Mg1/3Ta2/3)O3-0.31PbTiO3 ceramics have been investigated. The dielectric constant and loss of poled ceramic samples were determined. The pyroelectric coefficient and the spontaneous polarization were measured by the static Byer-Roundy method as a function of temperature. The piezoelectric d33 and coupling factor (kp) were measured by using the Berlincourt d33 meter and resonance-antiresonance method, respectively. The Curie temperature and pyroelectric peak temperature decreased gradually with the addition of Bi2O3. The maximum dielectric and pyroelectric constant increase sharply with addition of 1 mole% Bi2O3 and then decrease gradually with further addition of Bi2O3. The PMT-PT specimen modified 3 mole% Bi2O3 showed a large voltage responsivity (Fv ∽ 0.1m2/C). The dissipation factor and piezoelectric constant could be improved by small additions of Bi2O3.

Dielectric, Pyroelectric and Piezoelectric Properties of 0.4Pb(Mg1/3Nb2/3)O3-0.3Pb(Mg1/3Ta2/3)O3-0.3PbTiO3 Ceramics Modified with Cr2O3

Dielectric, pyroelectric and piezoelectric properties of the 0.4Pb(Mg1/3Nb2/3)O3-0.3Pb(Mg1/3Ta2/3)O3-0.3PbTiO3 ceramics modified with Cr2O3 have been investigated. The dielectric constant and loss of ceramic samples were determined. The pyroelectric coefficient and spontaneous polarization were measured using the static Byer-Roundy method as a function of temperature. Small amounts of Cr2O3 promoted grain growth of the ternary base composition. Dielectric, pyroelectric and piezoelectric properties of the base composition were improved with the addition of small amounts of Cr2O3.

Dielectric and pyroelectric properties in the Pb(Mg1/3Ta2/3)O3-PbZrO3 system

Abstract Dielectric and pyroelectric properties in the solid solution (1-x) Pb(Mg1/3Ta2/3)O3:xPbZrO3(PMT-PZ) are studied as a function of temperature. The stability of the perovskite phase was studied as a function of sintering temperature. The dielectric constant and loss of poled samples were determined. The addition of PbZrO3 affects the dielectric and pyroelectric properties of PMT system and the transition temperature is continuously shifted to higher temperature with increase of a small amount of PbZrO3. The composition with maximum dielectric constant exhibits the high pyroelectric coefficient

Effect of vanadium doping on dielectric, pyroelectric and piezoelectric properties of 0.66Pb(Mg1/3Ta2/3)O3-0.34PbTiO3 ceramics

Abstract Sintering behavior and electrical properties of 0.66Pb(Mg1/3Ta2/3)O3-0.34PbTiO3 ceramics were investigated as a function of the amount of V2O5. The optimum conditions for obtaining samples with high densities and improved electrical properties occur at sintering temperature of 1100°C/4h using a nominal addition of 0.6wt % V2O5. The dielectric and pyroelectric peak temperatures are slightly shifted to lower temperatures with the addition of amounts of V2O5. All compositions show a broad maximum for the dielectric constant. The composition with the maximum dielectric and pyroelectric constant exhibits relatively superior piezoelectric properties.

Dielectric, pyroelectric and piezoelectric properties in the Pb(Mg1/3Nb2/3)O3-Pb(Mg1/3Ta2/3)O3-PbTiO3 system

Abstract Dielectric, pyroelectric and piezoelectric properties of relaxor ferroelectric in the 0.4Pb(Mg1/3Nbm)O3-(0.6-x)Pb(Mg1/3Ta2/3)O3-xPbTiO3 solid solution series have been investigated. The dielectric constant and loss of poled ceramic samples were determined. The pyroelectric coefficient and the spontaneous polarization were measured by the static Byer-Roundy method as a function of temperature. The electromechanical coupling factor(kp) and piezoelectric d33 were measured by using the resonanceantiresonance method and Berlincourt d33 meter, respectively. The transition temperature is continuously shifted to higher temperature with increase of a small amount of PbTiO3. The composition with the maximum piezoelectric constant exhibits the high dielectric and pyroelectric constant

Synthesis and dielectric properties in the 0.65Pb(Mg1/3Ta2/3)O3-0.35PbTiO3 system modified with BaO

Abstract The correlation between the sintering temperature, grain size, and dielectric properties of relaxor ceramics in the 0.65Pb1-xBax(Mg1/3Ta2/3)O3-0.35PbTiO3 solid solution series have been investigated. The stability of the perovskite phase was studied as a function of sintering temperature. Sintering studies at different temperatures revealed that the dielectric constant increased with increasing grain size in these ceramics. The dielectric constant at Tc increases with additions of BaO up to 1 mol% and then decreases with further additions of BaO. The pyroelectric and piezoelectric properties of this system were improved by adding a small amount of BaO

Dielectric, piezoelectric, and pyroelectric properties of Sr-doped PMT-PT solid solution ceramics

Dielectric, piezoelectric and pyroelectric properties of 0.65(Pb/sub 1-x/Sr/sub x/)(Mg/sub 1/3/Ta/sub 2/3/)O/sub 3/-0.35PbTiO/sub 3/ (0/spl les/x/spl les/0.12) solid solution near the morphotropic phase boundary (PMT-PT) have been investigated. Dielectric constant and loss of poled ceramic samples were determined. The electromechanical coupling factor and piezoelectric d/sub 33/ constant were measured for various compositions in the ceramics. The pyroelectric coefficient and spontaneous polarization were measured by the static Byer-Roundy method as a function of temperature. The values of dielectric constant, piezoelectric d/sub 33/ constant and pyroelectric coefficient for Sr-doped PMT-PT are larger compared to the values observed for undoped PMT-PT ceramics. Transition temperature is continuously shifted to lower temperature with increase of a small amount of SrCO/sub 3/.