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In this study, electric field-induced thickness strain of pure polyurethane (PU), carbon black C/PU composite and ferroelectric PZT/PU composite have been compared. The three compositions have been submitted to whether a bipolar electric field (0.1 Hz), whether a voltage step. Both C and PZT loading improves the strain of the pure polymer matrix. However, PZT filling yields the highest dynamic strain...
To embedded ferroelectric random access memories in the 65-nm CMOS and beyond, three-dimensional structure and low-temperature formation have been developed. As the semiconductor technology moves toward the 65-and 45-nm nodes, the role of nonvolatile memories embedded in system-on-a-chips (SoCs) is becoming extremely important. Especially in ferroelectrics, bismuth-layered perovskite materials such...
Polarization reversal in Pb(Zr, Ti)O3 ferroelectric films was followed by a novel technique of cross-sectional piezoelectric force microscopy (PFM). Instead of the traditional scanning of the top surface of ferroelectric thin films, the domain structure across the cross section is visualized. The probing AC electric field is applied to the capacitor structure between top and bottom electrodes resulting...
Low temperature crystallization of chemical solution derived Bi1.5Zn0.5Nb1.5O6.5 films by using pulsed laser annealing was achieved. The effects of laser energy density, irradiation time and film thickness on the sample structure and electrical properties were systematically studied. Crystallized films were obtained with laser irradiation at room temperature, but laser induced defects degrade the...
Point defect migration is considered as a mechanism to yield aging in ferroelectrics. Different from magnetic systems, ferroelectric domains can be pinned by free charges at the perimeter of otherwise homogeneous grains or crystals. This clamping is shown to be stronger due to the reorientation of defect dipoles. Clamping stresses are calculated to be in the range of 106 to 107 Pa in a uniaxial model...
The importance of a high shear coefficient d15 to the piezoelectric properties of domain-engineered perovskite crystals is discussed. The terms "rotator" and "extender" are introduced to differentiate the contrasting behaviors of 4mm BaTiO3 and PbTiO3. In "rotator" ferroelectrics, where d15 is high, polarization rotation is the dominant mechanism of piezoelectric response;...
A metrological approach for the determination of effective material parameters for piezoelectric multilayer actuators is presented. The elastic, dielectric and coupling constants S33E, ??33S, ??33T, e33 and d33 are determined systematically for different constellations of mechanical and electrical prestress and sinusoidal excitation. Device losses are taken into account by treating all parameters...
La-doped BiFeO3 (BLFO) thin films have been deposited on Pt (111)/TiO2/SiO2/Si (100) substrates under different oxygen pressure of 5 mTorr - 50 mTorr by the pulsed-laser deposition (PLD). The effects of oxygen pressure on crystal structure and ferroelectric properties have been investigated. X-ray diffraction analysis shows that the BLFO thin films are of pure perovskite phase with tetragonal structure...
Morphotropic phase boundary composition KNaNbO3-LiTaO3-LiSbO3 (KNN-T-LS) thin films were grown by Pulsed Laser Deposition on niobium doped conductive SrTiO3 substrates. Using X-ray diffractometry, the phase evolution, stoichiometry, and growth orientation were monitored for various deposition conditions including temperature and ambient oxygen partial pressure. The results indicate that the scattering...
The Pb0.9La0.1Ti0.975O3 (PLT10) thin films were grown on Pt/Ti/SiO2/Si(100) substrates by using RF magnetron sputtering. The crystalline and domain properties of PLT10 thin films were studied by using X-ray diffraction (XRD) and piezoresponse force microscopy (PFM). It was found that the head-to-tail polarization configurations exist constantly in PLT thin films, indicating that the low electrical...
Polycrystalline lead zirconate titanate (PZT) thin films were synthesized on titanium substrates at a processing temperature of 160 ??C for 16 hours by using a hydrothermal method. The effects of KOH concentration on the phase evolution and morphology of the films were investigated. The as-synthesized PZT thin films using KOH concentration of 4 mol/1 have a dielectric constant and loss of 515 and...
A new process for the sputter deposition of Pb(Zr, Ti)O3 (PZT) thin films from a composite target has been demonstrated. PZT thin films deposited by this sputter technique are compared to those deposited by a standard sol-gel method to determine the suitability of the sputter deposition process, with its inherent advantages, for device manufacturing. Half micron PZT films were deposited by both methods...
Multilayer piezoelectric transformers (MPT) were manufactured using PZN-PMN-PZT ceramics and their electrical properties were then investigated according to frequency and load resistance. The voltage step-up ratio of multilayer piezoelectric transformer showed the maximum value in the vicinity of 73 kHz and increased according to the increase of load resistance. When the output impedance coincided...
Bi4Ti3O12 (BIT) thick films have been successfully prepared on Pt/ZrO2 substrates by the screen printing technique. Pt bottom and Ag top electrodes were also fabricated at 1300degC for 1 h and 850degC for 10 min by screen printing pastes, respectively. The influence of excess Bi2O3 as a sintering aid was investigated in this study. Screen printable pastes were prepared by kneading appropriated proportions...
The ferroelectric properties under uniaxial compressive pre-stress and scaling behavior of commercial soft PZT ceramics are investigated. The ferroelectric properties under the uniaxial compressive pre-stress of the ceramics are observed at stress up to 24 MPa using a compressometer in conjunction with a modified Sawyer-Tower circuit. The results show that the ferroelectric characteristics, i.e. the...
Pyrochlore-free lead zirconate titanate -lead zinc niobate ceramics have been systematically investigated in the as-sintered condition as well as after annealing. The ceramics were characterized by dielectric spectroscopy and Sawyer-Tower polarization (P-E) measurements. The powders of Pb[(Zr1/2Ti1/2)1-x-(Zn1/3Nb2/3)x], where x = 0.1, 0.3 and 0.5 were prepared using the columbite -(wolframite) precursor...
A series of lead magnesium niobate-lead titanate ((1-x)Pb(Mg 1/3Nb 2/3)O3-xPbTiO3) relaxor ferroelectrics (PMN-PT) are being used in the composite design of a stable high temperature high permittivity ceramic dielectric. However, pure PMN has a dielectric maximum no lower than -10degC. To extend this range to lower temperatures niobium was replaced with tantalum. The tantalum-based component (PMTa-PT)...
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