• Journal of the Korean Ceramic Society
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• 제35권7호
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• pp.665-670
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• 1998

Ferroelectric anomaly in PbO-{{{{ { {B }_{2 }O }_{3 } }}-{{{{ {TiO }_{3 } }}-BaO glasses which is observed in DAT measurements was in-vestigated together with the effect of BaO content on the shift of Cuire temperature. The temperature where the ferroelectric anomaly apperars on cooling in DTA decreased in proportion with increasing BaO content,. For as-crystallized samples the ferroelectric anomaly was not observed on heating but on cooling whilist for powder samples leached chemically from the crystallized samples both endothermic and ex-otehrmic peaks were observed. This fact suggests that the appearance of the ferroelectric anomaly in DAT largely depends on glassy phases surrounding individual {{{{ {PbTiO }_{3 } }} crystals rather than effects of grain size and crystallinity.

• Smart Structures and Systems
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• 제11권2호
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• pp.185-197
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• 2013

We developed a simultaneous strain measurement and damage detection technique using a pair of surface-mounted piezoelectric transducers and a fiber connecting them. This is a novel sensor configuration of the fiber acoustic wave (FAW) piezoelectric transducer. In this study, lead-zirconate-titanate (PZT) transducers are installed conventionally on a plate's surface, which is a technique used in many structural health monitoring studies. However, our PZTs are also connected with an optical fiber. A FAW and Lamb wave are simultaneously guided in the optical fiber and the structure, respectively. The dependency of the time-of-flight of the FAW on the applied strain is quantified for strain sensing. In our experimental results, the FAW exhibited excellent linear behavior and no hysteresis with respect to the change in strain. On the other hand, the well-known damage detection function of the surface-mounted PZT transducers was still available by monitoring the waveform change in the conventional Lamb wave ultrasonic path.

• Transactions on Electrical and Electronic Materials
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• 제7권2호
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• pp.72-75
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• 2006

Ferroelectric PZT heterolayered thick films were fabricated by the alkoxide-based sol-gel method. PZT(Zr/Ti=60/40) paste was made and alternately screen-printed on the $Al_2O_3$ substrates. We have introduced a press-treatment to obtain a good densification of screen printed films. The porosity of the thick films was decreased with increasing the applied pressure and the thick films pressed at $0.6ton/cm^2$ showed the dense microstructure and thickness of about $76{\mu}m$. The relative dielectric constant increased with increasing the applied pressure. The remanent polarization and coercive field increased with increasing applied pressure and the values for the PZT thick films pressed at $0.6ton/cm^2$ were $16.6{\mu}C/cm^2$, 76.9 kV/cm, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.469-470
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• 2006

Piezoelectric transformers based on lead zirconate titanate(PZT) have been received considerable interest because of their wide potential applications in transformer, oscillator, resonance sensor, actuator, acoustic transducer, as well as active slider for hard disk drives. However, for the applications which need a small power supply such as thin and flat displays, micro-robot, micro-system, it is especially necessary to integrate the passive components because they typically need more than 2/3 of the space of the conventional circuit. So, we have fabricated the piezoelectric micro-transformer to supply energy for micro-systems using PZT thin films and MEMS technologies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.223-224
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• 2006

In this study, we have investigated the micromachining of PZT to fabricate interdigitated electrodes of electro active material actuator using Nd:YAG laser We have observed groove shapes of PZT with changing beam power, scanning speed, gas, and so on to find optimum conditions of the laser processing for PZT grooves. As a result, this method has been applied to the laser micromachining for grooves in PZT surface, and we could have optimum parameters of Nd:YAG laser Finally it was shown that the laser micromachining of PZT can substitute fer bonding, etching and deposition processes in fabricating electro active material actuator embedded with interdigitated electrodes.

• Proceedings of the KIEE Conference
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.802-805
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• 1988

The objective of the present study was to manufacture the piezoelectric composites of Lead Zirconate Titanate (PZT) - polymer for applications such as ultrasonic medical diagnosis and hydrophone. The PZT rod-polymer composites have been prepared with 4.5 to 57 volume percent PZT using 1.5 mm rod, so the connectivity pattern of the two phase is 1-3 type. The electromechanical coupling factors of radial mode ($k_{p}$) and thickness mode ($k_{t}$) were nearly independent of the volume percent PZT, which were 0.3 and 0.65, respectively. The acoustic impedance of the piezoelectric composites was measured by the resonance technique in the frequency range 50 KHz-1.5 MHz, which was in the range of 3.8 - 60 Mrayl.

• Journal of the Korean Ceramic Society
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• 제26권6호
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• pp.829-835
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• 1989

Devitrifing solder glasses in a specific group of glass ceramic materials are extensively used in hermetically sealing alumina electronics packages. Preferred frit glass compositions of this study consist of 37~40wt% PbO, 35~40wt% ZnO, 18~20wt% B2O3, 1~3wt% SiO2, 0~6wt% TiO2. The coated frit glasses crystallize during firing and form a strong hermetic seal. DTA and X-ray diffraction were used to characterize crystallization of the glass frit. Frit seal containing 2wt% TiO2 has crystallization temperature of 550~57$0^{\circ}C$ with surface nucleation. Frit seal containing 6wt% TiO2 has crystallization temperature of 515~5$25^{\circ}C$ with bulk nucleation, and the main crystalline phase was perovskite lead titanate having minus expansion coefficient. The average activation energy for the crystallization calculated from Ozawa equation was 65$\pm$10kcal/mol.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.155-158
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• 2002

Eu-doped lead zirconium titanate $Pb_{1.1}(Zr_{0.3}Ti_{0.7})O_{3}$ thin films on the Pt/Ti/$SiO_2$/Si substrates prepared by a metalorganic decomposition (MOD) method. The effect on the structural and electrical properties of the films measured according to Eu content. Eu-doping altered significantly the dielectric and ferroelectric properties. The remanent polarization and coercive field decreased with increasing the concentration of Eu content. The dielectric constant and dielectric loss of the film decreased with increasing Eu contents. The 3 mol% of Eu-doped PZT thin film showed large remanent polarization and the fatigue characteristic of the film did not change up to $10^9$ switching cycles.

• The Korean Journal of Ceramics
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• 제3권3호
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• pp.213-217
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• 1997

In this paper, the imparct of X-ray and plasma process-induced-damages to La doped Lead Zirconate Titanate (PLZT, (Pb1-xLa)(Zr0.5Ti0.5)O3) capacitor characteristics have been investigated from the viewpoint of gigabit scale dynamic random access memory (DRAM) applications. Plamsa damage causes asymmetric degradation on hysteresis characteristics of PLZT films. On the other hand, X-ray damage results in a symmetrical reduction of charge storage densities (Qc's) for both polarities. As La concentration increases in the films, the radiation hardness of PLZT films on X-ray and plasma exposures is improved. It is observed that the damaged devices are fully recovered by thermal annealing under oxygen ambient.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 한국반도체및디스플레이장비학회 2006년도 춘계학술대회
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• pp.194-197
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• 2006

Lead-free bismuth-layered perovskite ferroelectric europium-substituted $Bi_{4}Ti_{3}O_{12}(BTO)$ thin films have been successfully deposited on Pt/Ti/$SiO_2$/Si substrate by a sol-gel spin-coating process. $Bi(TMHD)_3,\;Eu(THMD)_3,\;Ti(OiPr)_4$ were used as the precursors, which were dissolved in 2-methoxyethanol. The thin films were annealed at various temperatures from $600^{\circ}\;to\;720^{\circ}C$ in oxygen ambient for 1 hr, which was followed by post-annealed for 1 hr after depositing a Pt electrode to enhance the electrical properties. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the crystallinity and surface morphology of layered perovskite phase, respectively. The remanent polarization value of the BET thin films annealed at $720^{\circ}C\;was\;25.95{\mu}C/cm^2$ at an applied voltage of 5 V.