L. Burianova

What is really measured on a d33-meter?

Abstract Mechanical boundary conditions of PZT sample are not well defined in the measurement process on a d33-meter due to the misfit in size or shape of the jaws and of the sample. Result of such d33 measurement is usually an effective value d 33 eff . Mechanical stress/strain conditions are simulated for PZT discs/cylinders in a d33-meter by the finite element method (ANSYS® software) and an effective d 33 eff is calculated and compared to the original input d33 value as well as to the values measured on a d33-meter (type ZJ-3C). Relative d 33 eff d 33 value seems to be more sensitive to the disc aspect ratio than to the PZT material type tested. Although such strong dependence on the aspect ratio has been found in simulations, it is not correlated with experiments. Coefficient d 33 eff is not significantly sensitive to the position of a d33-meter metallic jaws with respect to the disc center.

Determination of the piezoelectric coefficients dij of PZT ceramics and composites by laser interferometry

Abstract We have measured the piezoelectric coefficients of PZT ceramics by resonance and laser interferometry methods. The surface displacement was measured by a single-beam Michelson interferometer. A stable double-beam interferometer was also used to suppress the effect of bending. The piezoelectric coefficients d ij of the PZT ceramic and of the 0–3 ceramic–polymer composites were determined from the displacements. The results for PZT d ij coefficients obtained by the both methods are in good agreement.

Study of the Inverse Flexoelectric Phenomena in Ceramic Lead Magnesium Niobate-Lead Titanate

The inverse flexoelectric phenomenon describes the generation of a mechanical deformation in an insulating solid by an applied gradient of the electric field. Lead magnesium niobate-lead titanate (PMNT) ceramic permits study of the inverse flexoelectric behavior because of its large flexoelectric coefficient. Special conical samples were prepared for the generation of a high electric field gradient and cylindrical samples with uniform field. A strong deformation is caused by the electrostrictive behavior of PMNT ceramic. An asymmetric butterfly-shaped strain dependence on electric field is observed at wide temperature range on the conical samples. For evaluation of converse flexoelectric coefficient μ 33 (in matrix notation) it is necessary to know elastic properties of ceramic. The ultrasonic measurements on ceramic samples were performed for this purpose. In this letter we also report measurements of temperature dependence of flexoelectric coefficient μ 33 . The measurements confirmed a great enhancement of μ 33 coefficient in PMN ceramics, which cannot be explained exclusively by the high permittivity of the ceramic.

On the precision of a new laser interferometer in a wide temperature range

Abstract The paper deals with the construction of an interferometer, which works in a wide temperature range using a helium optical cryostat, and with the accuracy of the strain measurements. The suppression of cooling system vibrations is a necessary condition for the measurements. The precision of the strain measurements of different piezoelectric samples (such as PMN-PT single-crystals, PZT ceramics, etc.) is discussed.

Piezoelectric, dielectric and pyroelectric properties of 0-3 ceramic-polymer composites

Abstract The circular samples of composites were made from PZT ceramic grains dispersed in polymers (epoxy or rubber). Pressure dependencies of the hydrostatic piezoelectric coefficient dh and permittivity ε were measured in the range up to 60 MPa. The hydrostatic strain coefficient dh, the hydrostatic voltage coefficient gh and figure of merit dh.gh were determined using the static method. The pressure dependence of the hydrostatic coefficients was measured for several successive cycles. Experimental dependence of the charge on pressure and temperature was fitted by multi parameter function. The pressure and temperature dependencies of the hydrostatic dh and pyroelectric p3 coefficients were determined. It was found that the hydrostatic strain coefficient dh and hydrostatic voltage coefficient gh decreased and pyroelectric coefficient p3 increased with pressure at constant temperature.

The piezoelectric coefficients in a wide temperature range by laser interferometry

The paper deals with the piezoelectric coefficients measurements of PZT type piezoelectric ceramics in a wide temperature range. The single beam micro-interferometer, working inside of helium optical cryostat in the range 150-330 K was used. The original design of optical cryostat was realized for the suppression of cooling system vibrations. The piezoelectric coefficients d 33 and d 31 were obtained by laser interferometer measurements of the sample strain, induced by an applied electric field. The temperature dependences of both d 33 and d 31 were fitted by polynomial function and hydrostatic piezoelectric coefficients d h were estimated from these fitted values. The temperature dependence of the piezoelectric coefficients can be used to study extrinsic and intrinsic contributions and their temperature behaviour. For this reason it is desirable to shift the low temperature limit down to 20 K and to increase the accuracy of the piezoelectric coefficients d 33 and d 31 measurement.

Dielectric Properties of PZN-PT Single Crystals Influenced by Electric Field in a Wide Temperature Range

The paper deals with phenomenological treatment of Lead Zinc Niobate—Lead Titanate (PZN:PT) crystals. Polarization and weak field permittivity as functions of temperature and bias electric field throughout the whole phase transitions range are of particular importance for the PZN-PT compositions behaviour close to the morphotropic phase boundary (MPB). The effect of DC bias field on phase transitions in PZN:PT solid solutions near the MPB was studied. A phase transition induced by electric field and associated changes in dielectric properties of PZN:PT were observed for different compositions of 4.5% and 8% PT. Relaxation behaviour was observed, too.

About the Measurements of the d 33 Piezoelectric Coefficient of the PZT Film--Si/SiO 2 /Ti/Pt Substrates Using an Optical Cryostat

The paper deals with a measurements of d 33 piezoelectric coefficient of the PZT film on substrate Si/SiO 2 /Ti/Pt, and its dependence on frequency and voltage in the room temperature. The measurements of the piezoelectric-induced displacements in the temperature range 240 K to 330 K were provided by a double beam miniaturized interferometer that was placed in optical helium cryostat. The PZT films were grown by RF magnetron sputtering. We tested three samples supported from IEMN-DOAE-MIMM (Univ. of Valenciennes). In all cases we observed smaller piezoelectric response than we expected. The d 33 coefficients were approximately 25 pC/N for 40b and 38b samples and about 130 pC/N for 39c sample. The response was nonlinear in applied voltage range and saturation value of electric field is about 100 kV/cm. Coefficient d 33 decreases with decreasing temperature and at 240 K is its value about 90% of value at room temperature.

Thin Pb(ZrxTi1− x )O3 (PZT) Rhombohedral Compositions Deposited on the Si-Substrate and Its Non-Linear Piezoelectric Response

This paper presents some nonlinear piezoelectric properties and strain simulation in lead zirconate-titanate Pb(Zr x Ti1 − x )O 3 (PZT) thin films, sputtered on the Pt/Ti/SiO 2 /Si substrates. The samples PZT (60/40), (111) orientation, rhombohedral phase composition, and PZT (54/46), (001) near MPB were prepared. Thicknesses of the samples under test were estimated as 1.1, 1.3 and 2.2 μ m respectively. For first characterizations, X-ray diffraction (XRD), piezoelectric hysteresis, capacitance-voltage C(V) and strain vs. temperature dependencies were carried out. The effective piezoelectric coefficient d 33, eff ≈ 110 pm/V was found for PZT (60/40), and d 33, eff ≈ 70 pm/V for PZT (54/46) at room temperature, if the biasing electric field goes slowly from the one state to opposite state by 10 mHz, using the monitoring field of the amplitude 0.09 MV/m and frequency 1 kHz. The non-linear behaviour of the PZT thin film, as the effective d 33, eff vs. electric field was investigated by double beam laser interferometer and optical helium cryostat. Comparing our previously obtained data, the results are discussed. As consequences, the strain distribution in active thin PZT film area under top electrode was provided by FEM (ANSYS 8.0) and demonstrated in the contribution. Simulation of the dynamic deformation of the active thin PZT film area was presented during the conference ECAPD8.

Elastic Stiffness Constants of PZN-4.5%PT Single Crystal Influenced by DC Bias Electric Field Applied at Various Directions to Prototypic Crystal Symmetry

The purpose of this work was to characterize an influence of the electric bias field on the elastic stiffness constants of important and unusual piezoelectric material Lead Zinc Niobate-Lead Titanate (PZN-PT). The longitudinal and transverse mode of sound propagation in single crystals containing 4.5% PT were studied. The influence of electric field, which poles the sample, is investigated by the pulse-echo sound propagation technique. From these measurements, the values of complex elastic stiffness constants are evaluated at different poling conditions with different frequencies for longitudinal and sheer excitations. Crystal cuts [001], [110] and [111] served for measurements of the elastic stiffness constants under application of the electric field. Aspects of field-induced phase transitions in PZN-4.5%PT single crystals at room temperature are discussed. Hysteretic behavior has an influence on attenuation and velocity of ultrasound.