| 1 | DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF LEAD-FREE(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)+x%Ce_(2)O_(3)+y%La_(2)O_(3)+z%Y_(2)O_(3) COMPOUNDS SYNTHESIZED BY SOL-GEL TECHNIQUE显示文摘(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)+x%Ce_(2)O_(3)+y%La_(2)O_(3)+z%Y_(2)O_(3) compounds(named BNT-BT-x/y/z)were synthesized by a sol-gel technique,for (x,y,z)=(0,0,0),(0.25,0.25,0.25),(0.25,0.5,0.5),(0.5,0.25,0.25)and(0.5,0.5,0.25).The structural variation according to the different system compositions is investigated by X-ray diffraction analyses.The results shows that the addition of Ce_(2)O_(3),La_(2)O_(3) or Y_(2)O_(3) in BNT-BT system,do not modify the crystalline structure,and a rhombohedral-tetragonal morphotropic phase boundary is maintained for different dopant addition.The BNT-BT-x/y/z-based ceramics sintered at relatively low temperature(1100℃)exhibit a good densification ratio.The optimum dielectric and piezoelectric properties are obtained with the BNT-BT-0.5/0.25/0.25 composition.High dielectric properties at room temperature(ε_(r)>1000)and low dielectric losses(tanδ<4×10^(-2))are obtained for this composition.This compound exhibits a piezoelectric constant d_(33) of 95 pC/N,a good polarization behavior is observed with high remanent polarization P_(r) of 9.21μC/cm^(2) and low value coercitivefield E_(c) of 2.66 kV/mm. | A.CHAOUCHI M.SAIDI S.D'ASTORG M.RGUITI C.COURTOIS | 2012 | Journal of Advanced Dielectrics2012，2，4： | 0 |
| 2 | Dielectric,ferroelectrics properties and impedance spectroscopy analysis of the[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)-based lead-free ceramics显示文摘Polycrystalline of[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)samples were prepared using the high-temperature solid-state reaction technique.X-ray diffraction(XRD)analysis indicates the formation of a single-phase with orthorhombic structure.AC impedance plots were used as tool to analyze the electrical behavior of the sample as a function of frequency at different temperatures.The AC impedance studies revealed the presence of grain effect,from 425℃onwards.Complex impedance analysis indicated non-Debye type dielectric relaxation.The Nyquist plot showed the negative temperature coefficient of resistance(NTCR)characteristic of NKLNT.The AC conductivity results were used to correlate with the barrier hopping(CBH)model to evaluate the binding energy(W_(m)),the minimum hopping distance(R_(min)),the density of states at Fermi level(N(E_(f))),and the activation energy of the compound. | M.Saidi A.Chaouchi S.D'Astorg M.Rguiti C.Courtois | 2015 | Journal of Advanced Dielectrics2015，5，1： | 0 |
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