• Title/Summary/Keyword: Electric field poling

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Temperature Stability of Electro-mechanical Coupling Factors of PZT Ceramics (PZT 세라믹스의 전기기계결합계수 온도 안정성에 관한 연구)

  • Lee, Gae-Myoung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.1
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    • pp.27-32
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    • 2014
  • In this paper, PZT piezoelectric ceramic specimens with 4 compositions (Zr/Ti=50/50, 53/47, 56/44, 58/42) in $Pb(Zr,Ti)O_3$ system were fabricated. We studied effects of poling strength and thermal aging on the temperature characteristics of eletromechanical coupling factor k31 of the specimens, which were poled with the DC electric fields, 1.5, 2.5 and 3.5 kV/mm respectively and thermally aged for an hour at $200^{\circ}C$. The eletromechanical coupling factor k31 of the specimen with the composition Zr/Ti= 53/47, nearest to the morphotropic phase boundary decreased the most greatly, irrelevant to the intensity of poling field, due to 1st thermal aging. And the temperature coefficient of eletromechanical coupling factor k31 was (-) in the tetragonal phase composition and (+) in the rhombohedral phase composition, which is reverse in the temperature coefficient of resonance frequency. It is interesting that eletromechanical coupling factor k31 of PZT ceramics is shown to be able to increase as temperature increase in the interval $-20{\sim}80^{\circ}C$.

Depolarization Mechanism of Alternating-current-poled Pb(Mg1/3Nb2/3)O3-PbTiO3 Single Crystals Measured using in-situ thermally Stimulated Depolarization Current (TSDC 방법을 이용한 AC 폴링된 PMN-PT 단결정의 디폴링 메커니즘 분석)

  • Lee, Geon-Ju;Kim, Hwang-Pill;Lee, Sang-Goo;Lee, Ho-Yong;Jo, Wook
    • Journal of Sensor Science and Technology
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    • v.29 no.1
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    • pp.59-62
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    • 2020
  • Currently, increasing attention is being paid to relaxor-based ferroelectric single crystals in photoacoustic images, especially for high-end applications. Among the crystals are (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-100xPT) single crystals located near their morphotropic phase boundary (x = 0.30-0.35) because of their ultrahigh piezoelectric and electromechanical coupling properties. The alternating current poling (ACP) treatment, rather than the conventional direct current poling treatment, has recently been spotlighted due to its effectiveness in enhancing the piezoelectric properties. So far, it has been suggested that the enhanced piezoelectricity originates from either a domain miniaturization to nanodomains or from an electric-field-induced monoclinic symmetry. In this study, we demonstrate by thermally stimulated depolarization current measurements that the effect of ACP is too complex to be explained using a single mechanism and that the proposed electric-field-induced monoclinic symmetry is unlikely to exist.

Acoustic Properties of Electrostrictive Buzzer Using PZN-BT-PT Ceramics (PZN-BT-PT 세라믹스를 이용한 전왜 BUZZER의 음향 특성)

  • 유준현;김현재;박창엽
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.1
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    • pp.50-55
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    • 1992
  • Piezoelectric Buzzer which has been generally used requires about 30kV/cm poling process and has the aging effects. In this study, 0.85 PZN - 0.10 BT - 0.05 PT system ceramics with additives of 0 - 2 wt% YS12TOS13T were fabricated and investigated on electromechanical coupling coefficient(kS1pT), electric field induced charge coefficient(dS131T), and sound level. As the results, in the 0.4 wt% YS12TOS13T added composition ceramics compared with the basic, kS1pT was increased from 0.355 to 0.39 and induced piezoelectric d constant increased from 204 to 220 x 10S0-12T (C/N) and sound level of electrostrictive Buzzer has the highest value of 71.5 dB under 8kV/cm bias electric field.

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A study on the fabrication of periodically poled Ti:LiNbO3 (PPLN) by the control of charge (전하량제어에 의한 주기적 분극반전 Ti:LiNbO3 (PPLN) 제작 공정에 관한 연구)

  • Kim, Won-Joung;Jung, Hong-Sik;Lee, Han-Young
    • Korean Journal of Optics and Photonics
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    • v.16 no.4
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    • pp.366-375
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    • 2005
  • A fabrication process of periodic electric field assisted poling of Ti-diffused channel waveguides in LiNbO3 (Ti:PPLN) has been developed and improved using a periodic 180o phase inversion along the z-axis. The zig for poling inversion and the Labview program of charge control have been devised. Pulse high voltage and duty cycle were adjusted based on the estimated charge required for poling inversion. Monitoring the change of leakage current under applied voltage less than the coercive voltage also minimized a breakdown.

Electrical Relaxation in Silica Glasses and Nonlinearity in Electrical Conductivity (실리카 유리의 전기이완 특성과 비선형적 전기전도도)

  • 신동욱
    • Journal of the Korean Ceramic Society
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    • v.36 no.9
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    • pp.923-929
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    • 1999
  • The cause of optical nonlinearity induced in thermally poled silica glass is believed to be the space charge polarization. Since the second order optical nonlinearity (electro-optic effect) can be used in optical switches the optical nonlinearity in silica glass has drawn a large attention. Space charge polarization occurs when an ionic conducting material is subjected to dc electric field by the blocking electrode. Thermal poling performed to induce the optical nonlinearity in silica glass is basically identical to the process generating space charge polarization. As a first step to understand the mechanism of space charge polarization in silica glass hence the induced optical nonlinearity the absorption currents as functions of time were measured for various types of silica glasses and analyzed by the theory of space charge polarization. It was found that the electrical relaxation exhibited a step by the space charge polarization in the relatively long time range and dielectric loss peak showed a maximum at a specific temperature which is depending on type of silica glass. It was turned out that this relaxation might be a cause of nonlinearity in electrical conductivity of silica glass.

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Poling Quality Evaluation of Periodically Poled Lithium Niobate Using Diffraction Method

  • Pandiyan, Krishnamoorthy;Kang, Yeon-Suk;Lim, Hwan-Hong;Kim, Byeong-Joo;Prakash, Om;Cha, Myoung-Sik
    • Journal of the Optical Society of Korea
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    • v.12 no.3
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    • pp.205-209
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    • 2008
  • We demonstrated a simple way of evaluating the duty cycle error in periodically polled lithium niobate(PPLN) based on the method of binary phase diffraction grating. To demonstrate this method, -Z face etched PPLN of desired periods were fabricated by the standard electric field poling technique. The etched PPLN was considered as a surface-relief binary phase grating. The diffraction patterns were recorded for different spatial locations along the length of the sample. The experimentally observed efficiencies of the diffracted orders were compared with the theoretically calculated values to estimate the duty cycle error.

Effects of Remanent Polarization State and Internal Field in Ferroelctric Film on the Hydrogen-induced Degradation Characteristics in Pt/Pb(Zr, Ti)O3/Pt Capacitor (강유전막의 잔류 분극 상태와 내부 전계가 Pt/Pb(Zr,Ti)O3/Pt 커패시터의 수소 열화 특성에 미치는 영향)

  • Kim, Dong-Cheon;Lee, Gang-Un;Lee, Won-Jong
    • Korean Journal of Materials Research
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    • v.12 no.1
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    • pp.75-81
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    • 2002
  • The ferroelectric properties of Pb(Zr,Ti)O$_3$[PZT] films degrade when the films with Pt top electrodes are annealed in hydrogen containing environment. This is due to the reduction activity of atomic hydrogen that is generated by the catalytic activity of the Pt top electrode. At the initial stage of hydrogen annealing, oxygen vacancies are formed by the reduction activity of hydrogen mainly at the vicinity of top Pt/PZT interface, resulting in a shift of P-E (polarization-electric field) hysteresis curve toward the negative electric field direction. As the hydrogen annealing time increases, oxygen vacancies are formed inside the PZT film by the inward diffusion of hydrogen ions, as a result, the polarization degrades significantly and the degree of P-E curve shift decreases gradually. The direction and the magnitude of the remnant polarization in the PZT film affect the motion of hydrogen ions which determines the degradation of polarization characteristics and the shift in the P-E hysteresis curve of the PZT capacitor during hydrogen annealing. When the remnant polarization is formed in the PZT film by applying a pre-poling voltage prior to hydrogen annealing, the direction of the P-E curve shift induced by hydrogen annealing is opposite to the polarity of the pre-poling voltage. The hydrogen-induced degradation behavior of the PZT capacitor is also affected by the internal field that has been generated in the PZT film by the charges located at the top interface prior to hydrogen annealing.

Optical Interferometric Characterization of Nonlinear Optical Polymer Thin Films

  • Wu, J.W.
    • Journal of the Korean Vacuum Society
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    • v.7 no.s1
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    • pp.149-155
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    • 1998
  • The linear electro-optic (EO) effect is one of the second-order nonlinear optical effects existing in a noncentrosymmetric macroscopic system. In a polymer thin film, the noncentrosymmetry is achieved by electric field poling. The magnitude of the linear EO response is determined through the orientational distribution function of hyperpolarizable molecular dipoles. The relation between the linear EO coefficient and the second-order nonlinear optical susceptibility is explained. Three different methods of measuring the linear EO coefficient of a poled nonliner optical polymer thin film are introduced and discussed. All of them make use of the interferometric technique, the difference being in the optical parameters which are interfering.

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Degradation of 0.2PMN-0.8PZT Multilayer Ceramic Actuators

  • Song, Jae-Sung;Koh, Jung-Hyuk;Jeong, Soon-Jong;Wee, Sang-Bong
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.1
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    • pp.6-9
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    • 2005
  • Aging characteristics of 0.2PMN-0.8PZT multilayer ceramic actuators (MCA) has been investigated by applying both triangular wave function for unpoled and unipolar wave for poling. P-E hysteresis loops of the MCA had been distorted after about 90 million cycles running in triangular wave function. Effective electromechanical coupling coefficient was calculated in resonant and anti resonant frequencies. And pseudo-piezoelectric constant $d_{33}$ was also estimated from the strain versus electric field characteristics. The crack growth of MCA was clearly observed along to the boundary between electrode and inactive area. That results were thought due to the internal tensile stress came from both actuation of $d_{33}$ mode and motion of Poisson ratio.

The electro-optic properites measurement of the side-chain polymer flim (측쇄결합 폴리머 필름의 전기광학 특성 측정)

  • 김광택;이소영;이남권;송재원;박이순;금창대
    • Korean Journal of Optics and Photonics
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    • v.9 no.4
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    • pp.215-220
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    • 1998
  • We proposed an in situ measurement set-up and technique to measure the various electro-optic(E-O) properties of the E-O polymer. Using the proposed measurement set-up, the electro-optic effect and birefringence of unpoled side-chain E-O polymer induced by the strong dc and ac electric field were observed. The dependence of the E-O coefficients on the various poling conditions were measured with real time. To evaluate the thermal stability of the poled polymer the relaxation of the E-O effect was measured and the result was compared with well known polymer materials. The proposed measurement reduces the number of experimental steps and saves measurement time.

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