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1 Nov 2004

Volume 96, Issue 9, pp. 4689-5381

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The morphotropic phase boundary and dielectric properties of the xPb(Zr1∕2Ti1∕2)O3-(1−x)Pb(Ni1∕3Nb2∕3)O3 perovskite solid solution

Naratip Vittayakorn, Gobwute Rujijanagul, Xiaoli Tan, Meagen A. Marquardt, and David P. Cann

J. Appl. Phys. 96, 5103 (2004); http://dx.doi.org/10.1063/1.1796511 (7 pages) | Cited 70 times

Online Publication Date: 28 October 2004

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The solid solution between the normal ferroelectric Pb(Zr1∕2Ti1∕2)O3 (PZT) and relaxor ferroelectric Pb(Ni1∕3Nb2∕3)O3 (PNN) was synthesized by the columbite method. The phase structure and dielectric properties of xPZT-(1−x)PNN where x=0.4–0.9 and the Zr∕Ti composition was fixed close to the morphotropic phase boundary (MPB) were investigated. With these data, the ferroelectric phase diagram between PZT and PNN has been established. The relaxor ferroelectric nature of PNN gradually transformed towards a normal ferroelectric state towards the composition 0.7PZT-0.3PNN, in which the permittivity was characterized by a sharp peak and the disappearance of dispersive behavior. X-ray diffraction analysis demonstrated the coexistence of both the rhombohedral and tetragonal phases at the composition 0.8PZT-0.2PNN, a new morphotropic phase boundary within this system. Examination of the dielectric spectra indicates that PZT-PNN exhibits an extremely high relative permittivity near the MPB composition. The permittivity shows a shoulder at the rhombohedral to tetragonal phase transition temperature TRT=195 °C, and then a maximum permittivity (36 000 at 10 kHz) at the transition temperature Tmax=277 °C at the MPB composition. The maximum transition temperature of this system was 326 °C at the composition x=0.9 with the relative permittivity of 32 000 at 10 kHz.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
77.80.B- Phase transitions and Curie point
61.66.Fn Inorganic compounds
64.70.K- Solid-solid transitions
81.30.Dz Phase diagrams of other materials
78.30.Hv Other nonmetallic inorganics

Polarized Raman scattering of highly [111]-oriented Pb(Zr,Ti)O3 thin films in the rhombohedral-phase field

Hyunjung Yi, Min G. Kim, Jung H. Park, and Hyun M. Jang

J. Appl. Phys. 96, 5110 (2004); http://dx.doi.org/10.1063/1.1790573 (7 pages) | Cited 9 times

Online Publication Date: 28 October 2004

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Highly [111]-oriented rhombohedral lead zirconate titanate [Pb(Zr1−xTix)O3; PZT] thin films were prepared on Pt(111)∕Ti∕SiO2∕Si substrates by suitably combining pulsed laser deposition with sol-gel coating. Two distinctive types of the backscattering geometry were employed for the polarized Raman scattering study: (i) normal backscattering in which the propagation direction of relevant phonons is parallel to the principal [111] polar axis of the rhombohedral 3m (C3v) point group for observing E(TO) phonons, and (ii) side-view backscattering in which the phonon-propagation direction is normal to the [111] direction for isolating A1(TO) phonons. Room-temperature Raman spectra of the [111]-oriented PZT 60∕40 film (with Zr∕Ti=60∕40) having the high-temperature rhombohedral form were examined and compared with those of the [111]-oriented low-temperature rhombohedral PZT 90∕10 film which is characterized by the tilting of oxygen octahedra about the principal [111] direction. Similarities and differences in the observed Raman spectra between these two distinctive films were examined in the light of the Raman selection rules for R3m and R3c space groups.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
77.22.Ej Polarization and depolarization
77.80.-e Ferroelectricity and antiferroelectricity
63.20.D- Phonon states and bands, normal modes, and phonon dispersion
78.66.Nk Insulators
78.30.Am Elemental semiconductors and insulators
78.30.Hv Other nonmetallic inorganics
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
81.15.Fg Pulsed laser ablation deposition

Monitoring of cement hydration by broadband time-domain-reflectometry dielectric spectroscopy

N. E. Hager and R. C. Domszy

J. Appl. Phys. 96, 5117 (2004); http://dx.doi.org/10.1063/1.1797549 (12 pages) | Cited 18 times

Online Publication Date: 28 October 2004

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The broadband complex permittivity is monitored continuously in hydrating cement paste over the frequency range of 10 kHz–8 GHz and from initial mixing to several weeks of cure. Measurements are made by time domain reflectometry (TDR) dielectric spectroscopy, using an adjustable capacitance sensor, which can be embedded in the material in situ. The results are fit to a relaxation model, which includes terms representing (1) a Cole-Davidson relaxation near 1 MHz, which grows initially and then decreases with an advancing cure; (2) a Debye relaxation near 100 MHz, which grows initially and then decreases with an advancing cure; (3) a free-water relaxation near 10 GHz, which decreases with an advancing cure; and (4) an ion conductivity and electrode polarization, which decreases with an advancing cure. The model is fit continuously as function of cure time extracting parameters for the relaxation amplitudes, relaxation frequencies, and distribution parameters as a function of cure time. The results are contrasted with measurements in tricalcium silicate and tricalcium silicate with varying ion content, revealing differences that may indicate the nature of the processes involved. Alternative methods for extracting reaction-rate information directly from the TDR transient are presented, providing a robust monitoring procedure usable in the field. Such methods are demonstrated using a variation in temperature and comparison with measurements of reaction heat obtained by calorimetry.
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81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
66.30.H- Self-diffusion and ionic conduction in nonmetals
77.22.Ch Permittivity (dielectric function)
82.30.Nr Association, addition, insertion, cluster formation

Are microbubbles necessary for the breakdown of liquid water subjected to a submicrosecond pulse?

R. P. Joshi, J. Qian, G. Zhao, J. Kolb, K. H. Schoenbach, E. Schamiloglu, and J. Gaudet

J. Appl. Phys. 96, 5129 (2004); http://dx.doi.org/10.1063/1.1792391 (11 pages) | Cited 16 times

Online Publication Date: 28 October 2004

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Electrical breakdown in homogeneous liquid water for an ∼100 ns voltage pulse is analyzed. It is shown that electron-impact ionization is not likely to be important and could only be operative for low-density situations or possibly under optical excitation. Simulation results also indicate that field ionization of liquid water can lead to a liquid breakdown provided the ionization energies were very low in the order of 2.3 eV. Under such conditions, an electric-field collapse at the anode and plasma propagation toward the cathode, with minimal physical charge transport, is predicted. However, the low, unphysical ionization energies necessary for matching the observed current and experimental breakdown delays of ∼70 ns precludes this mechanism. Also, an ionization within the liquid cannot explain the polarity dependence nor the stochastic-dendritic optical emission structures seen experimentally. It is argued here that electron-impact ionization within randomly located microbubbles is most likely to be responsible for the collective liquid breakdown behaviors.
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77.22.Jp Dielectric breakdown and space-charge effects
72.20.Ht High-field and nonlinear effects
77.84.Nh Liquids, emulsions, and suspensions; liquid crystals

Temperature stability of the piezoelectric and elastic response of dc biased [001] and [110] oriented Pb(Zn1∕3Nb2∕3)O3‐PbTiO3 single crystals

Ahmed Amin and Dwight Viehland

J. Appl. Phys. 96, 5140 (2004); http://dx.doi.org/10.1063/1.1789271 (4 pages) | Cited 7 times

Online Publication Date: 28 October 2004

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Temperature and field dependent investigations of the longitudinal electromechanical properties of [001]- and [110]-oriented 0.955Pb(Zn1∕3Nb2∕3)O3‐0.045PbTiO3 single crystals have been performed. Electromechanical equivalence was found between [001] and [110] orientations in the ferroelectric rhombohedral FEr phase region, but not in the ferroelectric tetragonal FEt one. A dc bias of 0.4 MV∕m did not affect this equivalence. Softening of the dielectric constant (K), piezoelectric coefficient (d33), and Young’s modulus (Y) were observed along both the [001] and [110] orientations in the FEr phase region on heating towards the FEt one. Above the FEr‐FEt phase transition, a significant anisotropy was observed in the electromechanical and elastic coefficients. These results demonstrate that the enhanced length extensional (33-mode) electromechanical coupling k33 of rhombohedral crystals far from the morphotropic phase boundary is not constrained to the 〈001〉 orientation, but rather to the (110) plane.
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77.65.Bn Piezoelectric and electrostrictive constants
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
68.55.-a Thin film structure and morphology
77.22.Ch Permittivity (dielectric function)
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
77.80.B- Phase transitions and Curie point
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