scholarly journals High aspect ratio lead zirconate titanate tube structures: I. Template assisted fabrication - vacuum infiltration method

2012 ◽  
Vol 6 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Vladimír Kovaľ
Keyword(s):  
Aspect Ratio ◽  
Lead Zirconate Titanate ◽  
High Aspect Ratio ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Vacuum Infiltration ◽  
Memory Storage ◽  
Pure Oxygen ◽  
Outer Diameter ◽  
Infiltration Method

Polycrystalline Pb(Zr0.52Ti0.48 )O3 (PZT) microtubes are fabricated by a vacuum infiltration method. The method is based on repeated infiltration of precursor solution into macroporous silicon (Si) templates at a sub-atmospheric pressure. The pyrolyzed PZT tubes of a 2-?m outer diameter, extending to over 30 ?m in length were released from the template using a selective isotropic-pulsed XeF2 reactive ion etching of silicon. Free-standing microtubes, partially anchored at the bottom of the Si template, were then crystallized in pure oxygen atmosphere at 750 ?C for 2 min using a rapid thermal annealer. The perovskite phase of the final PZT tubes was confirmed by X-ray diffraction (XRD) analysis. The XRD spectrum also revealed a small amount of the pyrochlore phase in the structure and signs of possible fluoride contamination caused most likely by the XeF2 etching process. The surface morphology was examined using scanning electron microscopy. It was demonstrated that the whole surface of the pore walls was conformally coated during the repeated infiltration of templates, resulting in straight tubes with closed tips formed on the opposite ends as replicas of the pore bottoms. These high aspect ratio ferroelectric structures are suggested as building units for developing miniaturized electronic devices, such as memory storage (DRAM trenched) capacitors, piezoelectric scanners and actuators, and are of fundamental value for the theory of ferroelectricity in systems with low dimensionality.

scholarly journals High aspect ratio lead zirconate titanate tube structures: II. Directed assembly via dielectrophoresis

2012 ◽  
Vol 6 (1) ◽  
pp. 43-51
Author(s):  
Vladimír Kovaľ
Keyword(s):  
Aspect Ratio ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
High Aspect Ratio ◽  
Colloidal Suspension ◽  
Lead Zirconate ◽  
Uniform Electric Field ◽  
Outer Diameter ◽  
Electrode Gap ◽  
Zirconate Titanate

This paper reports on the controlled manipulation of high aspect ratio ferroelectric microtubes on pre-patterned templates by dielectrophoresis. Microtubes of ferroelectric lead zirconate titanate (PZT, a chemical formula of Pb(Zr0.52Ti0.48 )O3) with an outer diameter of 2 ?m, a length of about 30 ?m and a wall thickness of 400 nm were prepared by vacuum infiltration method using macroporous silicon templates. To position and align tubes at designed places, an alternating electric field was applied to a colloidal suspension of PZT tubes through lithographically defined microelectrodes. This would enable creation of a stable electrical connection to individual tubes for making a testing structure for rapid electrical characterization. Electric-field assisted assembly experiments demonstrated that the frequency and magnitude of the applied electric field control dielectrophoretic long-range forces, and hence spatial movement of the tubes in a non-uniform electric field. The most efficient biasing for the assembly of tubes across the electrode gap of 12 ?m was a square wave signal of 5 Vrms and 10 Hz. By varying the applied frequency in between 1 and 10 Hz, an enhancement in tube alignment was observed due to possible changes in dielectrophoretic torque. The results indicate a great potential for utilizing dielectrophoresis in construction of more complex, hierarchical 3-D device structures using the PZT 1-D like tubes as the building units.

Fluid Manipulation by Bio-Mimetic Cilia

2007 ◽  
Author(s):  
Kieseok Oh ◽  
Jae-Hyun Chung ◽  
Santosh Devasia ◽  
James J. Riley
Keyword(s):  
Aspect Ratio ◽  
Lead Zirconate Titanate ◽  
High Aspect Ratio ◽  
Small Volume ◽  
Lead Zirconate ◽  
Maximum Displacement ◽  
Assembly Method ◽  
Fluidic Device ◽  
Structure Assembly ◽  
Fluid Manipulation

This paper describes the fabrication and actuation of bio-mimetic cilia for fluid manipulation. High aspect ratio cilia made of polydimethylsiloxane (PDMS) were successfully assembled in a microfluidic device by our novel fabrication method. This method was to release the PDMS cilia from a Si mold and assemble the cilia in a device. All the process was performed under water in order to avoid the stiction and pairing of the PDMS cilia. The underwater assembly method enabled a high aspect ratio PDMS structure assembly in a fluidic device. The PDMS cilia were actuated in air and water by lead-zirconate-titanate (PZT) microstage. In the fabricated device, the maximum displacement of the cilia was observed at 120Hz in air and at 50Hz in de-ionized (DI) water with our experimental condition. The actuated cilia in a solution produced convective and propulsive fluid flow near the cilia structure. The developed device can be used for precise handling of small volume sample (e.g., 1 μL).

Effect of Pb Content on the Fatigue Properties of D.C. Reactive Sputtering-Derived PZT Thin Films

2006 ◽  
Vol 326-328 ◽  
pp. 613-616
Author(s):  
Dae Jin Yang ◽  
Seong Je Cho ◽  
Jong Oh Kim ◽  
Won Youl Choi
Keyword(s):  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Fatigue Behavior ◽  
Ferroelectric Properties ◽  
Pyrochlore Phase ◽  
Reactive Sputtering ◽  
Lead Zirconate ◽  
Fatigue Properties ◽  
Pzt Thin Films ◽  
Pzt Films

Lead zirconate titanate (Pb(Zr0.48Ti0.52)O3 or PZT) films were grown on platinized silicon wafers (Pt/SiO2/Si) by d.c. reactive sputtering method with multi targets. The Pb content of PZT films has been widely recognized as affecting not only the phase formation and microstructure but also the dielectric and ferroelectric properties. Pb content of PZT films was controlled by the variation of Pb target current. The relation between Pb content and Pb target current was expressed as y=0.89x-11.09. The x and y are Pb target current and Pb content, respectively. The pyrochlore phase was transformed to perovskite phase as Pb content was increased. This phase transformation improved the ferroelectric properties of PZT films. In PZT films with perovskite phase, fatigue properties were not improved with excess Pb content. Fatigue properties of PZT films began to be fatigued after 106 switching cycles and coincided with the typical PZT fatigue behavior. Excess Pb content (Pb vacancy) did not affect the fatigue properties of PZT films.

Influence of aspect ratio on effective electromechanical coupling of nanocomposites with lead zirconate titanate nanowire inclusion

2011 ◽  
Vol 22 (16) ◽  
pp. 1879-1886 ◽  
Author(s):  
Clark Andrews ◽  
Yirong Lin ◽  
Haixiong Tang ◽  
Henry A. Sodano
Keyword(s):  
Aspect Ratio ◽  
Mechanical Loading ◽  
Polymer Matrix ◽  
Lead Zirconate Titanate ◽  
Coupling Coefficient ◽  
High Aspect Ratio ◽  
Electromechanical Coupling ◽  
Lead Zirconate ◽  
Electromechanical Coupling Coefficient ◽  
Curved Surfaces

Piezoelectric ceramics offer exceptional sensing and actuation properties, however, they are prone to breakage and are difficult to apply to curved surfaces in their monolithic form. One method to alleviate these issues is through the use of 0–3 active composites, which are formed by embedding piezoelectric particles into a polymer matrix that protects the ceramic from breaking under mechanical loading. This class of material offers certain advantages over monolithic materials; however, they have seen little use due to the low electromechanical coupling offered by these materials. Here, we demonstrate that by controlling the aspect ratio of the filler, the electromechanical coupling coefficient can be significantly improved. For all volume fractions tested, nanocomposites with high aspect ratio lead nanowires filler had higher coupling with increases as large as 2.3 times. Furthermore, the nanocomposite’s coupling was more than 50% of the piezoceramic fillers’ when nanowires were used.

Chemical Modification of Alkoxide Precursors for Lead Zirconate Titanate Formation

1996 ◽  
Vol 49 (5) ◽  
pp. 569
Author(s):  
S Tursiloadi ◽  
H Imai ◽  
H Hirashima
Keyword(s):  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Lead Zirconate ◽  
Significant Feature ◽  
Metal Alkoxide ◽  
Titanium Tetraisopropoxide ◽  
Zirconate Titanate ◽  
Diffraction Peaks ◽  
Alkoxide Precursors

Lead zirconate titanate (PZT) gel monolith was prepared by partially hydrolysing metal alkoxide solutions which were modified with acetylacetone ( acacH ). Lead diisopropoxide zirconium tetrabutoxide and titanium tetraisopropoxide were used as starting materials. After aging of the translucent monolithic gel at room temperature for several days or drying at 90°C for 18 h, the most significant feature in the infrared spectrum is the presence of bands at about 1550 cm-1 which can be assigned to the v(C-O) and v(C-C) vibrations of the acetylacetonate group coordinated to the metal cations of titanium and zirconium. Diffraction peaks of PbO were found after heating at 300°C for 2 h. After heating at 450°C for 2 h, diffraction peaks of pyrochlore Pb2Ti2O6 and perovskite PZT phases were observed. The diffraction peaks of PbO and the pyrochlore phase disappeared after heating at 600°C, and the tetragonal perovskite phase was stable up to 1000°C. Diffraction peaks of the perovskite phase were also found after heating at 430°C for 24 h.

Micro-Robotic Actuation Units Based on Thin-Film Piezoelectric and High-Aspect Ratio Polymer Structures

2014 ◽  
Author(s):  
Minchul Shin ◽  
Jongsoo Choi ◽  
Ryan Q. Rudy ◽  
Christopher Kao ◽  
Jeffrey S. Pulskamp ◽  
...  
Keyword(s):  
Thin Film ◽  
Aspect Ratio ◽  
Lead Zirconate Titanate ◽  
High Aspect Ratio ◽  
Low Voltage ◽  
Weight Bearing ◽  
Lead Zirconate ◽  
Dynamic Responses ◽  
Low Voltage Operation ◽  
Fabrication Procedure

A fabrication procedure is presented for creating microactuation elements that link piezoelectric thin-films with high-aspect ratio parylene microstructures. Resulting actuators permit relatively large rotational motions for low voltage operation, while maintaining large weight-bearing capacity. Actuator fabrication is performed on a silicon wafer though a combination of metal and thin-film lead-zirconate-titanate (PZT) deposition and patterning, parylene refill of high-aspect ratio trenches, and dry release of moving parts from the silicon substrate. Static and dynamic responses of various test structures are measured, to estimate material properties of the integrated PZT-polymer structures, for use in future actuator modeling and optimization.

Kinetics of formation of the pyrochlore and perovskite phases in sol-gel derived lead zirconate titanate powder

1998 ◽  
Vol 13 (8) ◽  
pp. 2170-2173 ◽  
Author(s):  
V. S. Tiwari ◽  
Arun Kumar ◽  
V. K. Wadhawan ◽  
Dhananjai Pandey
Keyword(s):  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Lead Zirconate ◽  
Oxygen Stoichiometry ◽  
X Ray ◽  
Zirconate Titanate ◽  
Kinetics Of Formation ◽  
Kinetics Of

Lead zirconate titanate (PZT) powder is prepared by the sol-gel method. The formation of pyrochlore and perovskite phases is investigated by high temperature x-ray diffraction (XRD) and thermal analysis techniques. The pyrochlore phase first appears in x-ray amorphous form, and then gets converted to crystalline state on annealing in air. We show that vacuum annealing of the pyrolyzed amorphous PZT gel suppresses the formation of the crystalline pyrochlore phase. This, in turn, enhances the kinetics of conversion of pyrochlore to perovskite, such that a pyrochlore-free perovskite phase can be obtained by annealing at about 500 °C. On the other hand, if annealing is carried out in air, a crystalline pyrochlore phase is formed, which requires annealing temperatures higher than 600 °C for transformation to the perovskite phase. These observations are explained tentatively in terms of the oxygen stoichiometry of the two phases.

Controlled fabrication of periodically high-aspect ratio CVD-diamond nanopillar arrays by pure oxygen etching process

2016 ◽  
Vol 155 ◽  
pp. 61-66 ◽  
Author(s):  
Peng Sun ◽  
Chengchun Tang ◽  
Xiaoxiang Xia ◽  
Zehan Yao ◽  
Baogang Quan ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Cvd Diamond ◽  
Etching Process ◽  
Pure Oxygen ◽  
Nanopillar Arrays ◽  
Oxygen Etching
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