Commentary on Section 264 of ITAA 1936: commissioner may require information and evidence
Dabner, Justin
2007-01-01
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35 records were found.
Piezoelectric composite materials, consisting of a ferroelectric ceramic in an
electrically-inactive polymer matrix, have been shown to greatly outperform single
phase materials for certain applications. A new assembly technique, which electrically
controls the spatial distribution of the ceramic within the polymer, promises to enhance
the sensitivity of 0-3 type piezoelectric composites. The materials so-produced have a
quasi 1-3 structure and it is intended that they will exhibit some of the advantages of 1-
3 piezoelectric composites, whilst retaining the simplicity of 0-3 manufacturing.
The electric field structuring technique exploits the electrokinetic phenomenon of
dielectrophoresis, which is responsible for the electrorheological effect. When a
suspension of ceramic particles in an insulating fluid is exposed to a moderate AC
e...
Planar-spiral piezoelectric-unimorph-actuators, that deflect out-of-their-plane, were
modelled, designed and fabricated. A range of other planar piezoelectric-device designs
has also been made. These include spokes, multi-arms, plates and swastikas. All these
devices consisted of a mechanical support in the plane with a piezoelectric layer
deposited on top. Impedance spectra demonstrated that a fabricated device was
piezoelectrically active. Finite-element (FE) models of straight and spiral piezoelectric-
unimorph-actuators were constructed. The mechanical stiffness of the spiral-beam was
increased with the curvature of the beam; consequently, the inner coils exhibited virtually
no deflection and appeared to be redundant. The advantage of the spiral-actuators is that
they allow large actuator lengths to be contained compactly without t...
The
target of this research work was to establish a surface integrity
control methodology in ultra precision grinding for piezoelectric materials, taking
into account the interaction between the material removal manner and the
machine
design contributions.
Whilst there are
many respective research works concerning the
microscopic material removal behavior on brittle materials and the design
characterization of individual machine components, it was necessary to identify
the
design characteristics in order to ensure a consistent and fine surface
integrity ( i.e. surface roughness, surface atness, textural damage ) in contact
machining.
For
example, in a thermal analysis of a machine structure, the
considerable inuences of internal and external heat sources were observed,
which resulted in heat ows in aerostatic and hydrostatic components...
Lead zirconate titanate
(PZT) is a oxide, which posseses a perovskite type structure.
The material is ferroelectric
making it technically useful for a diverse range of
applications from thermal imaging to non-volatile integrated memory devices. Thin
films of PZT are
commonly deposited onto platinised-silicon (Pt(111)/Ti/SíOX/Si)
bottom electrodes
by chemical solution deposition (CSD). Depending on the
conditions used a transient intermetallic
phase Pt3Pb can form in-situ with a (111)
preferred orientation during processing, which reduces the lattice mismatch between
the desired
perovskite phase and bottom electrode. Thereby, making it easier for the
perovskite phase to both nucleate and take on a preferred (111) orientation.
In the work
presented experiments were conducted on modifying the surface of
platinised-silicon to achieve a bet...
The objective of this work was twofold, i.e. to develop an aqueous route for tape casting Lead Ziconate Titanate (PZT)ceramics for pyroelectric applications and to optimise the die-pressing route for reducing defect size and number in bulk Lead Zicronate Titanate ceramics (PZT).
We have investigated the effects of Mn doping on the ferroelectric properties of Pb(Zr0.3Ti0.7)O3 (PZT) thin films on substrates Pt/Ti/SiO2/Si. Small amount of Mn-doped (≤1 mol%) PZT (PMZT) showed almost no hysteretic fatigue up to 1010 switching bipolar pulse cycles, coupled with excellent retention properties. We present evidence that while a low permittivity interfacial layer forms between the Pt electrode and PZT films, this does not occur in PMZT. We propose that Mn dopants are able to reduce oxygen vacancy mobility in PZT films and Mn2+ ions consume the oxygen vacancies generated during repeated switching, forming Mn4+ ions. These mechanisms are probably responsible for their low observed fatigue characteristics.
Using an atomic force microscope (AFM) modified to perform PiezoAFM we have investigated the piezoelectric response of sol-gel thin film lead zirconate titanate (PZT 30/70, PbZr0.3Ti0.7O3) on Pt–Ti/SiO2/Si, indium tin oxide (ITO)/glass and Pt/MgO. The films were produced by spin coating a PZT 30/70 sol and firing at 520 °C for Pt electrode systems and 600 °C for the ITO system. By conducting PiezoAFM hysteresis loops we have shown that the localised piezoelectric response varies for PZT on differing substrates. The degree of asymmetry in the hysteresis loops varies for each substrate, as do the coercive fields. The coercive fields have been found to be ±18 V/μm for PZT/ITO/glass, +22 and −18 V/μm for PZT/Ti-Pt/SiO2/Si and +35 and −20 V/μm for PZT/Pt/MgO. The PZT grown on Pt/MgO, Pt-Ti/SiO2 and ITO/glass shows an offset or asymmetric hy...
PZT was grown on STP (Si/SiO2/Ti/Pt (Ti 5nm, Pt 100nm)), SAP (Si/Si3N4/Al/Ti/Pt
(Al 100nm, Ti 10nm, Pt 15nm)) and GI (Glass/ITO(Indium Tin Oxide)). In each
case the PZT underwent the same heat treatment, 200ºC for 2 minutes and then
530ºC for 5 minutes. The extent of perovskite formation was evaluated using
Piezoresponse force microscopy (PFM). This provided information about the
domain orientation and spatial distribution of ferroelectric material in the PZT film.
This showed that PZT/STP underwent complete transformation to the perovskite
phase. However, for the PZT/SAP and GI incomplete transformation to the
perovskite occurred. A system of rosettes surrounded by an amorphous matrix
developed. The size and density of the PZT rosettes on the surface was found to
be substrate dependent. For Gi/PZT the density of rosettes formation is ...
Thick PZT films (1 - 20 m) have been prepared using a composite sol gel
technique whereby PZT powder and a PZT producing sol are formed into a slurry
and spin coated onto silicon wafers. The maximum relative permittivity obtained
was approximately 80% of that exhibited by bulk PZT of comparable composition.
However, the d 33, f and e 31, f [1] piezoelectric coefficients were shown to be
significantly lower than that of bulk PZT. It has been proposed that the
measured value of d 33, f is affected appreciably by particle-particle rotation
and substrate clamping leading to reduced poling efficiency which may also
greatly reduce the value of e 31, f observed. Samples with high levels of
porosity have been shown to exhibit a reduced value of d 33 . This was
attributed to 31 and 51 mode piezoelectrically generated charges caused by the
bendi...
The pyroelectric, dielectric and DC resistive properties of Sb and Cr-doped ceramics with a base composition of Pb(Mg1/3Nb2/3)0.025(Zr0.825Ti0.175)0.975O3 have been studied. Sb doping has been shown to produce a linear reduction in Curie temperature (TC=−22z+294 °C) with concentration (z) and to give an increase in pyroelectric coefficient from 250 to 310 μCm−2 K−1 for z increasing from 0 to 3 at.%. It also produces first a reduction and then an increase in both dielectric constant and loss, so that the 33 Hz pyroelectric figures of merit (FOM's) are as follows: FV peaks at 3.8×10−2 m2 C−1 and FD peaks at 1.2×10−5 Pa−1/2. The resistivity is increased substantially from 1.1×1011 to ca 6×1011 Ωm with 1 at.% Sb, thereafter changing little. The behaviour has been explained in terms of Sb acting as a donor ion, reducing oxygen vacancy conce...
