Papers by Keyword: PZT

Abstract: A new process was developed for fabrication of multiferroic 1-3 type nanostructured composite films. In this process, eletrodeposition method was adopted to prepare the arrays of cobalt nanowires as ferromagnetic composition. The images, phase structure and magnetic properties were characterized by SEM, XRD and VSM, respectively. The results showed that applying magnetic field during electrodepostion process could improve the alignment and height uniformity of nanowires arrays, inducing (002)-orientation growth. The PZT (53/47) precursor solution prepared for ferroelectric composition was infiltrated the spaces between nanowires. After annealed at 700 °C for 20 min, the 1-3 type multiferroic composite film was achieved. Preliminary results show this technique to have the potential to become a practical fabrication process for 1-3 type multiferroic composite films.

Abstract: Piezoelectric sensor can produce voltage when deflected (function as an energy harvester) while piezoelectric actuator can deflect when a voltage is applied. Different device applications have different requirements on the thickness and in-plane geometry of the Lead Zirconate Titanate(PZT) piezoelectric layers and thus have their own processing difficulties. In this paper, PZT-Au-Si cantilever is fabricated by eutectic bonding and dicing process.The properties of lapped PZT ceramics and silicon cantilever is also evaluated. The PZT-Au-Si cantilever applications for both piezoelectric actuators and energy harvesters have been confirmed.

Abstract: This study examined the effect of crystalline orientation and dopants such as Nb and Zn on the piezoelectric coefficient of sol-gel driven Pb1(Zr0.52Ti0.48)O3(PZT) and doped PZT thin films. Crack-free 1-μm-thick PZT and doped PZT thin films prepared by using 2-Methoxyethanol-based sol-gel method were fabricated on Pt/Ti/SiO2/Si substrates. The highly (111) oriented PZT thin films of pure perovskite structure could be obtained by controlling various parameters such as a PbTiO3 seed layer and a concentration of sol-gel solution. The Nb-Zn doped PZT thin films exhibited high piezoelectric coefficient which was about 50 % higher than that of undoped PZT thin film. The highest measured piezoelectric coefficient was 240 pC/N, which could be applicable to piezoelectrically operated MEMS actuator, sensor, or energy harvester devices.

Abstract: The effect of adding Al2O3 to the PZT-PMN solid solution material for use for ceramic resonator was investigated. It has been found that when the amount of Al2O3 added to PZT-PMN is 0.3　wt% or below, it exists inside the crystal lattice as Al3+ ion and increases the stability of oscillation frequency over application of heat (heat resistance). It has been found that when more than 0.3　wt% of Al2O3 is added, the Al3+ ion that remained undoped will exist at grain boundary as secondary phase, and increase the strength.

Abstract: Conductivity measurements were carried out on Mn-doped PZT ceramics in order to investigate the changes in defect chemistry with annealing, by identifying the charge carriers such as lead or oxygen vacancies. PZT compositions were prepared by sol-gel method in rhombohedral region Pb(Zr0.56 Ti0.44)O3 with Mn contents 0.4, 0.8, 1.5 and 2 wt.%. Nano-sized powder (~21nm) was obtained after calcination and bulk density values of >98% were achieved upon sintering. It was found that nitrogen annealing reduced the electrical conductivity strongly as compared to oxygen and air annealing and the possible charge carriers were single ionised oxygen vacancies along with and vacancies.

Abstract: For an optimum performance of MEMS devices such as microactuators and microsensors based on piezoelectric thin films a Si/Ti/Pt bottom electrode is widely used. This study shows temperature dependence of surface morphology of both platinum bottom electrode and piezoelectric lead titanate zirconate (PZT) thin films. Ti (10 nm) and Pt (100 nm) thin films were deposited on silicon substrate by thermal evaporation and electron beam, respectively, without vacuum breaking. After annealing treatment, the Pt film exhibited (111) preferred orientation. Finally a 0.8 micron thick PZT (54/46) films were deposited by r.f. magnetron sputtering at room temperature in pure Ar followed by a conventional post annealing treatment on silicon substrate. The XRD measurements have shown the perovskite structure of PZT films with (100) preferred orientation growth. The roughness of platinum film measured by AFM test showed the continuous smoothness of platinum surface for different annealing temperatures. The SEM test results demonstrated that irrespective of the annealing temperature increases, recrystallization of platinum and nano-size holes on Pt surface occurred. The latter caused the acceleration of out-diffusion titanium atoms through Pt layer and reach to the other side of surface. The surface state of Pt thin film is very important as it could strongly influence the PZT surface morphology so the existence of bubbles and depression on PZT surface are increased with both recrystallization of Pt grains and nano-size holes on Pt film surface when the annealing temperature increased.

Abstract: In the present study a complete analysis of the morphological and electrical properties of PZT layers with composition 53Zr-47Ti is presented. Three different samples composed of 3, 6, and 9 PZT layers were analyzed on a substrate consisting of ZrO2-SiO2-Si structures. The PZT and ZrO2 layers were deposited via Sol-Gel, whereas the SiO2 layer, on every sample, was deposited via PECVD. SEM results showed morphology of very small granules on the 3 layered thin-film samples (12 nm), on the 6 layered thin-film samples a mixture of small and large size (100-300 nm) granule formation was observed, with the 9 layered thin-film samples exhibiting very large granule sizes (bigger than 300 nm). XRD results showed that increasing the number of deposited layers caused an incremental increase on the detected peak intensities, aided in the promotion of the perovskite phase, and diminished the presence of the pyrochlore phase. It was also observed, during electrical measurements, that increasing the number deposited layers directly increased the overall capacitance of the thin-film structure. This effect was attributed primarily to the large amount of perovskite and large size of grains presented on thick samples.

Abstract: This work analyzes the processing of Pb(Zr,Ti)O3 (PZT) thin films directly on copper-coated polymer films. PZT thin film deposition was performed onto the metallized Kapton® films using a single RF plasma jet. In order to reduce the interaction of PZT and Cu during the initial growth stage, an ultrathin amorphous TiO2-x seeding layer was sputter-deposited prior to PZT deposition. The film texture was a mixture of (111)-oriented perovskite nanocrystals, rutile and pyrochlore. Topography and piezoelectric in-plane and out-of-plane response of the films were evaluated using a commercial AFM adapted for piezoforce measurements. The as-deposited films were self-polarized with polarization pointing at the surface of the sample. Polarization was switchable and a piezoelectric hysteresis was obtained.

Abstract: In order to perform the growth position control, PbTiO3 (x=0) (PTO) nanocrystals were deposited on atomically flat and non-atomically flat -Al2O3 substrates by RF magnetron sputtering. The atomically flat substrates with atomic steps and terrace are expected to induce the lateral growth along a terrace between the surface steps. In the case of the atomically flat, the nanocrystals got lined up along the atomic steps, and uniform nanocrystals were obtained on surface in same pitch.

Abstract: Ceramic solid solutions within the system (1-x)PZT-xBT, where x = 0.1, 0.2, 0.3, 0.4 and 0.5, were prepared by conventional mixed-oxide method combined with a two-stage sintering procedure. A sintering time of 2 h at 1000 °C followed by a second step in the temperature range of 1000-1200 °C for 2 h was employed to all samples and compared to the one-step sintering process. Phase formation, densification and microstructure of all ceramics were examined via X-ray diffraction (XRD), Archimedes method and scanning electron microscope (SEM). The results lead to the conclusion that the pure perovskite phase and high densification of (1-x)PZT-xBT ceramics with fine grain can be successfully achieved under suitable two-stage sintering conditions.