Abstract: Fine-scale 1-3 PZT/epoxy piezoelectric composites were prepared by a dice-fill process, and
their resonance characteristics and dynamic piezoelectric properties were investigated. The resonance
characteristic was deeply influenced by PZT volume fraction and the thickness of 1-3 PZT/epoxy
composite. The experiments proved that reducing the distance between PZT rods and/or increasing the
height/width ratio could weaken the additional coupling effect of lateral resonance mode on thickness
mode. The PZT/epoxy composites displayed only thickness-mode resonance when the distance between
PZT rods was reduced to 220μm and its aspect ratio was increased up to 10.
Abstract: The effects of A-site cation size disorder in ABO3 type ferromagnetic metallic
La0.55Ca0.45MnO3 system have been studied by substituting La3+ and Ca2+ by other ions, while keeping
the valency of Mn ions and the A-site cation mean radius constant in the substituted compounds
with different A-site ionic radii variance σ2 = Σi (xiri
2 − 2), where xi and ri are the atomic fraction and
ionic radii of i-type ions at A-site, respectively. It is revealed that the A-site disorder induces the
decreasing of the magnetization and the increasing of the resistivity. The ferromagnetic Curie point TC
decreases with the increasing of the A-site ionic radii variance, too. Moreover, the ground state of the
system transits from ferromagnetic metal to glass insulator upon increasing variance of the A-site ionic
radii from 0.0003 for La0.55Ca0.45MnO3 to 0.009 for Gd0.55Sr0.45MnO3. It is argued that the suppression of
the ferromagnetism is ascribed to the enhanced radial distortion of the MnO6 octahedra due to the
increasing A-site disorder.
Abstract: Electric fatigue of piezoelectric ceramics is very important for piezoelectric actuator
applications in strong field. In order to classify the fatigue of ferroelectric and piezoelectric properties, the
electric fatigue behavior of piezoelectric ceramics of PZT-PMN-PNN was investigated under bias and
unipolar pulse cycling field. The bias and unipolar polarization hysteresis loops are measured before and
after cycling. The polarization measurements after cycling show a much smaller decrease than bipolar
fatigue, but the piezoelectric coefficient d33 still suffers relatively higher deterioration, which indicates
different characteristics for piezoelectric and ferroelectric fatigues. A possible mechanism of the partial
pining of switching domains responsible for the difference is discussed in this paper.
Abstract: Bipolar electric fatigue in ferroelectric niobium-doped lead zirconate titanate stannate
ceramics was investigated. Variations in the polarization and strain hysteresis loops as well as
microstructural modifications of the material due to the electric cycling were analyzed. Compared
with ferroelectric PZT ceramics cycled under similar conditions, the material exhibited a higher
resistance to electric fatigue. Properties of the specimens showed significant decays above 106.5 cycles.
Asymmetric suppression of strain hysteresis loop was monitored. At 108 cycles, the remanent
polarization, the right maximum strain and the left maximum strain decreased to 70%, 58% and 44%
of their initial values, respectively. The color of the material was changed from pale yellow to dark
grey with cycling. The properties and color of the fatigued samples were recovered almost fully to
those of the virgin state after a heat treatment at 500oC for 1 h. The pinning of domain walls, probably
by oxygen vacancies, was concluded to be the predominant fatigue mechanism for the material.
Abstract: Propagation and deflection of microcracks driven by electric loading in <001>-oriented
0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 ferroelectric single crystals were investigated using an in-situ
transmission electron microcopy (TEM) technique. The static observation of the domain pattern
revealed the coexistence of sub-micrometer and nano-meter domains. Electric field induced deviation
from the main microcrack path and subsequent propagation along the direction almost perpendicular
to the electric field were observed directly. A qualitative analyses is given based on the maximum
energy release rate criterion.
Abstract: A comparison experiment was conducted in which some lead zirconate titanate (PZT)
piezoelectric ceramic rings were simply immersed in a 0.01 M NaOH solution while other PZT rings
were immersed in the solution with a 50 Hz AC voltage applied between the electrodes of the rings
and a counter electrode in the solution. Though the simple immersion showed no noticeable influence
on the PZT rings, those PZT rings treated with the application of the AC voltage were obviously
degraded in their piezoelectric properties. It was proposed that the degradation resulted from the
collaborated reactions of atomic hydrogen and oxygen generated in the AC voltage-induced
electrolysis of water. Water may be an important origin for degradation of piezoelectric ceramic
devices operating under AC voltages.
Abstract: Degradation aging of BaTiO3 microwave ceramic capacitors for EMI applications at highvoltage,
AC 10kV, was focused in this paper. Electric performances of the ceramic capacitors were
systematically evaluated with thermal shock (5 cycles of –30 °C for 1 h and then 125°C for 1 h), damp heat
(100% RH at 40°C for 500 h), and, endurance at high temperature (DC 10 kV at 100°C for 500 h). High
reliability for the ceramic capacitor was obtained with optimal ceramic composition, sintering
temperature, epoxy resin, curing agent and additives, which was satisfied with practical microwave
Abstract: Ba0.6Sr0.4TiO3 (BST) thin films deposited on Pt/Ti/SiO2/Si substrates by radio frequency
magnetron sputtering and crystallized by rapid thermal annealing (RTA) exhibit much thinner BST/Pt
interfacial transition layer and higher dielectric properties than the films crystallized by conventional
thermal annealing (CTA). HRTEM observations show that the transition layer is 2-3nm thick for RTA
and 4-5nm thick for CTA. XPS investigations display that the transition layer is composed of perovskited
BST phase and non-perovskited BST phase, and RTA corresponds to much less non-perovskited BST
phase than CTA. The reason for non-perovskited BST phase and the dielectric properties of BST films are
Abstract: A series of ferrroelectric-ferromagnetic composites were synthesized from BaTiO3 and
NiFe2O4 ferrite by conventional solid-state route. XRD studies indicated that the composites comprised of
only two phases, BaTiO3 phase with perovskite structure and NiFe2O4 phase with spinel structure. Frequency
dependence of permittivity and permeability were also measured. Experimental results showed
that the dielectric constant and initial permeability of these composites could be tunable by varying the
composition of composites. Thus, these composites can be used for multilayer chips EMI filters.
Abstract: Ferroelectric PZT heterolayered thick films were fabricated by the alkoxide-based sol-gel
method. PZT(20/80) and PZT(80/20) paste were made and alternately screen-printed on the alumina
substrates. The coating and drying procedure was repeated 4 times to form the heterolayered thick films.
The thickness of the PZT heterolayered thick films was approximately 60 μm. All PZT thick films showed
the typical XRD patterns of a perovskite polycrystalline structure. The relative dielectric constant and the
dielectric loss of the PZT thick films sintered at 1050oC were 283 and 1.90%, respectively.