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Jürgen Rödel - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent ferroelastic switching of soft Lead Zirconate titanate
Acta Materialia, 2009Co-Authors: Kyle G Webber, Emil Aulbach, T Key, Mie Marsilius, Torsten Granzow, Jürgen RödelAbstract:The longitudinal strain and polarization of a soft polycrystalline ferroelectric ceramic (Lead Zirconate titanate, PZT) were measured under uniaxial compressive stress at elevated temperatures utilizing a novel testing fixture. Ferroelectric ceramics have not previously been characterized under these conditions due to experimental complexity. In addition to nonlinear macroscopic constitutive behavior, the linear elastic moduli have been measured throughout the loading cycle, allowing for the determination of the relative contributions from the linear and nonlinear ferroelastic behavior as a function of stress and temperature. Experimental results show a strong temperature dependence of ferroelastic switching. The ferroelastic properties of unpoled and poled materials for temperatures up to the Curie point are contrasted with the spontaneous strain, elucidating the role of tetragonality in ferroelastic switching. When thermal changes are considered, marked changes in the maximum strain are observed.
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correlation of small and large signal properties of Lead Zirconate titanate multilayer actuators
Acta Materialia, 2009Co-Authors: Ingo Kerkamm, Torsten Granzow, P Hiller, Jürgen RödelAbstract:Polarization and strain hysteresis curves of Lead Zirconate titanate (PZT) multilayer actuators were obtained for both bipolar and unipolar electrical loading as a function of applied uniaxial compressive stress. These large-signal dielectric and piezoelectric properties are correlated with the corresponding small-signal properties of longitudinal piezoelectric coefficient d33 and longitudinal dielectric permittivity e33. A complete comparison is afforded by obtaining the small-signal properties as functions of both applied DC electrical field and uniaxial compressive stress. Results are presented in terms of guidelines for optimal performance of multilayer actuators, but also in terms of a qualitative description correlating the hysteresis of the piezoelectric coefficient with the macroscopic strain.
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evolution of bias field and offset piezoelectric coefficient in bulk Lead Zirconate titanate with fatigue
Applied Physics Letters, 2005Co-Authors: Yong Zhang, I S Baturin, Vladimir Ya Shur, Doru C Lupascu, Emil Aulbach, Jürgen RödelAbstract:Hysteresis loops of the piezoelectric coefficient, d33=f(E3), are measured on virgin and fatigued Lead Zirconate titanate ceramics. Four parameters are directly extracted from the measurements: internal bias field Eb, offset piezoelectric coefficient doffset, coercive field Ec, and remnant piezoelectric coefficient dr. The reduction in dr displays the decreasing switchable polarization with fatigue cycling. Eb and doffset are found to be linearly related. After thermal annealing, both offsets disappear, while the increase in Ec and the reduction in dr withstand annealing. The microscopic entities responsible for the offsets are less stable than those for reduced switching.
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effect of poling direction on r curve behavior in Lead Zirconate titanate
Journal of the American Ceramic Society, 2004Co-Authors: Sergio Luis Dos Santos E Lucato, Doru C Lupascu, Jürgen RödelAbstract:R-curves of Lead Zirconate titanate (PZT) have been measured with compact tension (CT) specimens for different poling conditions and grain sizes. Depending on poling direction the plateau value of the R-curves ranged from 1.13 to 1.54 MPa·m1/2 for a grain size of 6.4 μm and from 1.14 to 1.30 MPa·m1/2 for a grain size of 5.2 μm. Poling in the thickness direction yielded the material with the highest fracture toughness while the direction parallel to the loading direction led to the lowest fracture toughness.
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Subcritical Crack Growth in Lead Zirconate Titanate
Journal of the American Ceramic Society, 2004Co-Authors: William S. Oates, Doru C Lupascu, Emil Aulbach, Christopher S. Lynch, Alain Brice Kounga Njiwa, Jürgen RödelAbstract:Subcritical crack growth in terms of velocity-stress intensity factor (ν-K) curves in Lead Zirconate titanate (PZT) were experimentally characterized on poled and unpoled compact tension specimens. The poled specimens were tested under open- and short-circuit electrical boundary conditions, which resulted in an increase in fracture toughness by 0.2 MPa.m 1/2 for the accessible velocity range (v = 10 -9 to 10 -4 m/s) in the open-circuit case. Subcritical crack growth of unpoled specimens was obtained under ambient (relative humidity = 35%) and dry (relative humidity 0.02%) conditions over a regime in stress intensity factor of 0.5 MPa.m 1/2 .
L. E. Cross - One of the best experts on this subject based on the ideXlab platform.
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thickness dependent electrical characteristics of Lead Zirconate titanate thin films
Journal of Applied Physics, 1995Co-Authors: K. R. Udayakumar, P J Schuele, J Chen, S B Krupanidhi, L. E. CrossAbstract:Ferroelectric Lead Zirconate titanate thin films of morphotropic phase boundary composition were fabricated through the sol‐gel spin‐on technique to study the thickness dependence of electrical characteristics. At saturation, the films exhibited a dielectric constant of 1300, dissipation factor of 0.03, Curie temperature of 366 °C, remanent polarization of 36 μC/cm2, coercivity of around 30 kV/cm, and dielectric breakdown strength of over 1 MV/cm. The temperature dependence of permittivity showed an anomalous behavior with annealing temperature. The high temperature dielectric behavior of the films were distinguished by smeared and stunted dielectric maximum.
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Dielectric, ferroelectric, and piezoelectric properties of Lead Zirconate titanate thick films on silicon substrates
Journal of Applied Physics, 1995Co-Authors: H. D. Chen, L. E. Cross, K. R. Udayakumar, J. J. Bernstein, L. C. NilesAbstract:This article reports the fabrication of thick films of Lead Zirconate titanate (PZT) on platinum‐buffered silicon substrates by screen printing. Crack‐free films, up to 12 μm on a single pass, show a dielectric permittivity of 200, tangent losses of 0.05, remanent polarization of 2.5 μC/cm2, and coercive field of 40 kV/cm. The field‐induced longitudinal piezoelectric coefficient d33 at 40 kV/cm dc bias and 4 kV/cm alternating field corresponded to 50 pC/N. The magnitude of the piezoelectric voltage coefficient g33, computed from the strain coefficient and dielectric permittivity, under the same conditions, was found to be 36×10−3 V m/N, higher than that of a poled PZT bulk ceramic in comparison. These results are promising for a broad variety of sensor applications.
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rapid thermal annealing of sol gel derived Lead Zirconate titanate thin films
Journal of Applied Physics, 1992Co-Authors: J Chen, K. R. Udayakumar, K G Brooks, L. E. CrossAbstract:Sol‐gel derived ferroelectric thin films of Lead Zirconate titanate have been annealed through the rapid thermal annealing (RTA) technique to investigate the effect of various annealing temperature‐time combinations. Crystallization of the film into the perovskite phase required 10 s at 600 °C and a mere 1 s at 700 °C. Rapid thermally annealed films recorded weak‐field permittivities greater than 1000, dissipation losses of 0.02–0.05, maximum remanent polarization of 29 μC/cm2, and coercive field around 40 kV/cm. RTA films are distinguished by superior breakdown strengths, and morphologically smoother surfaces. The frequency dependent dielectric constants have been discussed in terms of a lumped circuit model.
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the extrinsic nature of nonlinear behavior observed in Lead Zirconate titanate ferroelectric ceramic
Journal of Applied Physics, 1991Co-Authors: Wenwu Cao, L. E. CrossAbstract:The nonlinear electric and electromechanical responses of Lead Zirconate titanate Pb(ZrxTi1−x)O3 ceramics to an external ac electric field have been measured under different driving levels. The onset of measurable nonlinearity is observed to be accompanied by the appearance of hysteresis loops. This lossy nature suggests that the nonlinearities in a ferroelectric ceramic are generated by the domain‐wall motion. In addition, aging experiments and the bias field dependence of the threshold field (onset of nonlinearity) all indicate the extrinsic nature of the nonlinear behavior of ferroelectric ceramics. A phenomenological theory of Arlt, Dederichs, and Herbiet [Ferroelectrics 74, 34 (1987)] has been extended to include the nonlinear contributions. With only 90° wall vibration being considered, the theory Leads to some basic understanding of the experimental results.
K. R. Udayakumar - One of the best experts on this subject based on the ideXlab platform.
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fabrication and electrical properties of Lead Zirconate titanate thick films
Journal of the American Ceramic Society, 1996Co-Authors: Daniel H Chen, Eric L Cross, K. R. Udayakumar, J. J. Bernstein, Christopher J Gaskey, L. C. NilesAbstract:Thick films of Lead Zirconate titanate of the morphotropic phase boundary composition, Pb(Zr0.52Ti0.48)O3, have been fabricated on platinum-buffered silicon using a modified sol–gel spin-coating technique. Crack-free films of 12-μm thickness can be uniformly deposited on 3-in.-diameter wafers with high yield and properties comparable to those of bulk ceramics. The thickness dependence of film structure and the dielectric, ferroelectric, and piezoelectric properties have been characterized over the thickness range of 1–12 μm. A strong (100) texture develops as film thickness increases above 5 μm; the films were marked by saturation values of longitudinal piezoelectric coefficient d33, 340 pC/N; remanent polarization, 27 μC/cm2; and dielectric permittivity, 1450. PZT films in this thickness range are extremely well-suited to application as electromechanical transduction media in silicon-based microelectromechanical systems (MEMS).
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thickness dependent electrical characteristics of Lead Zirconate titanate thin films
Journal of Applied Physics, 1995Co-Authors: K. R. Udayakumar, P J Schuele, J Chen, S B Krupanidhi, L. E. CrossAbstract:Ferroelectric Lead Zirconate titanate thin films of morphotropic phase boundary composition were fabricated through the sol‐gel spin‐on technique to study the thickness dependence of electrical characteristics. At saturation, the films exhibited a dielectric constant of 1300, dissipation factor of 0.03, Curie temperature of 366 °C, remanent polarization of 36 μC/cm2, coercivity of around 30 kV/cm, and dielectric breakdown strength of over 1 MV/cm. The temperature dependence of permittivity showed an anomalous behavior with annealing temperature. The high temperature dielectric behavior of the films were distinguished by smeared and stunted dielectric maximum.
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Dielectric, ferroelectric, and piezoelectric properties of Lead Zirconate titanate thick films on silicon substrates
Journal of Applied Physics, 1995Co-Authors: H. D. Chen, L. E. Cross, K. R. Udayakumar, J. J. Bernstein, L. C. NilesAbstract:This article reports the fabrication of thick films of Lead Zirconate titanate (PZT) on platinum‐buffered silicon substrates by screen printing. Crack‐free films, up to 12 μm on a single pass, show a dielectric permittivity of 200, tangent losses of 0.05, remanent polarization of 2.5 μC/cm2, and coercive field of 40 kV/cm. The field‐induced longitudinal piezoelectric coefficient d33 at 40 kV/cm dc bias and 4 kV/cm alternating field corresponded to 50 pC/N. The magnitude of the piezoelectric voltage coefficient g33, computed from the strain coefficient and dielectric permittivity, under the same conditions, was found to be 36×10−3 V m/N, higher than that of a poled PZT bulk ceramic in comparison. These results are promising for a broad variety of sensor applications.
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rapid thermal annealing of sol gel derived Lead Zirconate titanate thin films
Journal of Applied Physics, 1992Co-Authors: J Chen, K. R. Udayakumar, K G Brooks, L. E. CrossAbstract:Sol‐gel derived ferroelectric thin films of Lead Zirconate titanate have been annealed through the rapid thermal annealing (RTA) technique to investigate the effect of various annealing temperature‐time combinations. Crystallization of the film into the perovskite phase required 10 s at 600 °C and a mere 1 s at 700 °C. Rapid thermally annealed films recorded weak‐field permittivities greater than 1000, dissipation losses of 0.02–0.05, maximum remanent polarization of 29 μC/cm2, and coercive field around 40 kV/cm. RTA films are distinguished by superior breakdown strengths, and morphologically smoother surfaces. The frequency dependent dielectric constants have been discussed in terms of a lumped circuit model.
Eric L Cross - One of the best experts on this subject based on the ideXlab platform.
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flexoelectric effect in ceramic Lead Zirconate titanate
Applied Physics Letters, 2005Co-Authors: Eric L CrossAbstract:Mechanical strain gradient generated electric polarization or flexoelectric effect was investigated in unpoled Lead Zirconate titanate (PZT) ceramics in the ferroelectric state by using a cantilevered beam based approach. Flexoelectric coefficient μ12 at room temperature was measured to be 1.4μC∕m in the PZT ceramic at small level of strain gradient. Temperature-dependent experimental investigations clearly showed that high dielectric permittivity in the ferroelectrics enhanced flexoelectric polarization: essentially a linear relation was found to exist between μ12 and dielectric susceptibility χ at lower permittivity level (2100–2800), while μ12 versus χ curve started to deviate from the straight line at the χ∼2800 and nonlinear enhancement of μ12 with χ was observed, with μ12 value reaching 9.5 at χ∼11000. The nonlinearity in the flexoelectric effect was associated with domain-related processes. It is suggested that flexoelectric effect can have a significant impact on epitaxial ferroelectric thin films and mesoscopic structures.Mechanical strain gradient generated electric polarization or flexoelectric effect was investigated in unpoled Lead Zirconate titanate (PZT) ceramics in the ferroelectric state by using a cantilevered beam based approach. Flexoelectric coefficient μ12 at room temperature was measured to be 1.4μC∕m in the PZT ceramic at small level of strain gradient. Temperature-dependent experimental investigations clearly showed that high dielectric permittivity in the ferroelectrics enhanced flexoelectric polarization: essentially a linear relation was found to exist between μ12 and dielectric susceptibility χ at lower permittivity level (2100–2800), while μ12 versus χ curve started to deviate from the straight line at the χ∼2800 and nonlinear enhancement of μ12 with χ was observed, with μ12 value reaching 9.5 at χ∼11000. The nonlinearity in the flexoelectric effect was associated with domain-related processes. It is suggested that flexoelectric effect can have a significant impact on epitaxial ferroelectric thin films...
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flexoelectric effect in ceramic Lead Zirconate titanate
Applied Physics Letters, 2005Co-Authors: Eric L CrossAbstract:Mechanical strain gradient generated electric polarization or flexoelectric effect was investigated in unpoled Lead Zirconate titanate (PZT) ceramics in the ferroelectric state by using a cantilevered beam based approach. Flexoelectric coefficient μ12 at room temperature was measured to be 1.4μC∕m in the PZT ceramic at small level of strain gradient. Temperature-dependent experimental investigations clearly showed that high dielectric permittivity in the ferroelectrics enhanced flexoelectric polarization: essentially a linear relation was found to exist between μ12 and dielectric susceptibility χ at lower permittivity level (2100–2800), while μ12 versus χ curve started to deviate from the straight line at the χ∼2800 and nonlinear enhancement of μ12 with χ was observed, with μ12 value reaching 9.5 at χ∼11000. The nonlinearity in the flexoelectric effect was associated with domain-related processes. It is suggested that flexoelectric effect can have a significant impact on epitaxial ferroelectric thin films...
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flexoelectric effect in ceramic Lead Zirconate titanate
Applied Physics Letters, 2005Co-Authors: Eric L CrossAbstract:Mechanical strain gradient generated electric polarization or flexoelectric effect was investigated in unpoled Lead Zirconate titanate (PZT) ceramics in the ferroelectric state by using a cantilevered beam based approach. Flexoelectric coefficient μ12 at room temperature was measured to be 1.4μC∕m in the PZT ceramic at small level of strain gradient. Temperature-dependent experimental investigations clearly showed that high dielectric permittivity in the ferroelectrics enhanced flexoelectric polarization: essentially a linear relation was found to exist between μ12 and dielectric susceptibility χ at lower permittivity level (2100–2800), while μ12 versus χ curve started to deviate from the straight line at the χ∼2800 and nonlinear enhancement of μ12 with χ was observed, with μ12 value reaching 9.5 at χ∼11000. The nonlinearity in the flexoelectric effect was associated with domain-related processes. It is suggested that flexoelectric effect can have a significant impact on epitaxial ferroelectric thin films and mesoscopic structures.
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strain gradient induced electric polarization in Lead Zirconate titanate ceramics
Applied Physics Letters, 2003Co-Authors: Eric L CrossAbstract:Strain-gradient-induced polarization or flexoelectricity was investigated in unpoled soft Lead Zirconate titanate (PZT) ceramic where the texture symmetry ∞∞m forbids macropiezoelectricity. Even under high strain gradient (1 m−1) the induced polarization is small (1.6 μC/m2) at 20 °C. Higher strain gradients induce ferroelastic poling and an additional extrinsic contribution to the flexoelectric coefficient μ12 raising the value from 0.5 to 2.0 μC/m. Cooling through the Curie point (TC) under maximum stress (80 MPa) where the peak permittivity (∼20 000) could raise μ12 to 20 μC/m, the equivalent electric field is still only ∼1 kV/m, inadequate to achieve significant ferroelectric poling. The situation may be different in thin PZT films where much larger strain gradients can occur.
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dielectric hysteresis from transverse electric fields in Lead Zirconate titanate thin films
Applied Physics Letters, 1999Co-Authors: Eric L Cross, J. J. Bernstein, Raanan A MillerAbstract:Excellent symmetric dielectric hysteresis is observed from Lead Zirconate titanate (PZT) thin films using transverse electric fields driven by interdigitated surface electrodes. The 1-μm-thick PZT films with a Zr/Ti ratio of 52/48 are prepared on ZrO2 buffered, 4-in.-diam silicon wafers with a thermally grown SiO2 layer. Both the ZrO2 buffer layer and PZT film are deposited by using a similar sol–gel processing. Remanent polarization of about 20 μC/cm2 with coercive field less than 40 kV/cm is obtained as measured using a triangle wave at 50 Hz. Thicker films are being developed and retention for the transversely polarized state is currently under study. One of the objectives of this study is to develop a large array of d33-driven unimorph sensing elements for a high-resolution acoustic imaging system.
Gilbert Fantozzi - One of the best experts on this subject based on the ideXlab platform.
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R-curve and subcritical crack growth in Lead Zirconate titanate ceramics
Materials Science and Engineering, 2009Co-Authors: Azeddine Hizebry, Malika Saadaoui, Hassan El Attaoui, Jérome Chevalier, Gilbert FantozziAbstract:R-curves and subcritical crack growth curves (V-KI) were determined for undoped, K doped (PKZT) and Nb doped (PNZT) Lead Zirconate titanate (PZT) ceramics and the results are discussed including the effect of doping, grain size and the polarisation state. A pronounced crack growth resistance was observed in the soft PNZT ceramic, which is attributed to ferroelastic domain switching. Subcritical crack growth in the studied PZT materials is governed by both environmentally stress-induced corrosion at the crack tip and the crack shielding due to domain switching. Increasing domain switching capacity by structural modification of the material (i.e. by donor doping or by increasing the grain size) or by poling sifts the V-KI curve to higher values of the stress intensity factor.
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Effect of Nb and K doping on the crack propagation behaviour of Lead Zirconate titanate ceramics
Journal of the European Ceramic Society, 2007Co-Authors: Azeddine Hizebry, Malika Saadaoui, Jérome Chevalier, H. El Hattaoui, Gilbert FantozziAbstract:In the present study, we investigated the effect of doping on the crack propagation behaviour of Lead Zirconate titanate ceramics (PZT), particularly crack growth resistance and slow crack growth. Three PZT grades were processed: an undoped PZT, a soft PZT doped with niobium, PNZT, and a hard PZT doped with potassium, PKZT. The composition was chosen close to that of the morphotropic phase boundary (MPB), known to give excellent electromechanical properties. The soft material showed an important crack growth resistance and its slow crack growth curve V-KI (crack velocity versus stress intensity factor, KI) is shifted toward higher values of KI. The results are discussed in terms of toughening due to ferroelastic domain switching under mechanical loading