• 한국재료학회지
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• 제12권8호
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• pp.613-616
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• 2002

The polarization properties of $BaTiO_3$ were investigated by using thermally stimulated depolarization current (TSDC) technique. Two peaks were observed at about 400 K (peak A) and 435 K (peak B) from TSDC spectra obtained from the temperature range of 280-500 K. Peak A shows a sharp decrease of TSDC due to extinction of spontaneous polarization above the phase transition temperature of $BaTiO_3$. The values of activation energy of peak A and peak B were calculated to be 0.70 eV and 0.87 eV respectively. From the results of TSDC measurement with a variation of polarizing electric field strength, we found that saturation of total current of TSDC was started from 3kV/cm. However, the amount of total current of TSDC was not affected by the variation of polarizing time.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.581-586
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• 1998

This paper describes athermally stimulated displacement current (TSDC) of arachidic acid(AA) and polyamic acid alkylamine salts(PAAS) Langmuir-Blodgett(LB) films, which is a precursor of polyimide(PI). The TSDC measurements of AA LB film were performed from temperature to about 11$0^{\circ}C$ at a rate of 0.2$^{\circ}C$/ｓ inside a vacuum chamber for a reference. And the TSDC measurements PAAS LB film were performed from room temperature to about 25$0^{\circ}C$ and temperature was increased at the same rate as that of AA LB film. They show that there are TSDC peaks at about 7$0^{\circ}C$ in the arachidic acid LB films, and at about 7$0^{\circ}C$ and 16$0^{\circ}C$ in the PAAs LB films. Results of these measurements indicate the one small peak at 7$0^{\circ}C$ is resulted from a softening of the alkyl group and the large peak at 16$0^{\circ}C$ is possibly due to dipole of C-O group in the PASS molecule. We have calculated the vertical component of the AA and PAAs L film out of the TSDC curves. It shows that the dipole moment of the AA LB film is about 70-mD at 7$0^{\circ}C$. And the dipole moment of PAAS LB film is about 040mD at 7$0^{\circ}C$ and about 200mD at 16$0^{\circ}C$ in the first measurement of TSDC. In the second measurement of TSDC of PASS LB film after cooling down to room temperature, the TSDC peaks are almost disappeared.

• 한국안광학회지
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• 제3권1호
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• pp.269-277
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• 1998

$Li_2B_4O_7$의 완화현상은 이온 깡총뛰기에 의한 것과, 공간전하에 의한 완화현상의 두 가지 종류가 나타나며 이들의 완화시간은 실온 이상에서 모두 $10^2sec$보다 짧은 것으로 보고되었다. 지금까지 논의되지 않은 매우 낮은 주파수 (mHz 혹은 Hz)에서 나타나는 완화현상을 관찰하기 위하여 $30{\sim}500^{\circ}C$ 온도영역에서 TSDC(Thermally Stimulated Depolarization Current) 특성에 관한 실험과 사각형 파의 바이어스 전압을 인가하였을 때의 유전특성 조사에 의하여 이온 및 전자 trap에 의한 완화특성을 논의하였다. TSDC 조사를 통하여 $Li_2B_4O_7$의 TSDC 전류곡선이 두 개의 anomaly를 갖고 있는 것으로 나타났다. TSDC 에서 나타난 anomaly는 공간전하보다 수천배나 더 긴 완화시간을 갖고 있는 것으로 밝혀졌으며 이 중 저온 쪽의 anomaly는 공간전하 층에 수입된 전자들이 양의 공간전하 층에 trap 되어 공간전하의 재 분포를 방해하는 역할을 하여 trap 되어 있던 전자와 이온이 서로 분리되면서 공간전하의 재 분포가 이루어지는 전도기구에 기인하는 것으로 여겨진다. 또한 고온쪽의 anomaly는 음의 전하운반자가 전극에 흡착되어 나타나는 완화 mechanism으로 생각된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 제2회 학술대회 논문집 일렉트렛트 및 응용기술전문연구회
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• pp.11-14
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• 2000

This paper describes a thennally stimulated displacement current(TSDC) of polyamic acid alkylamine salts(PAAS) Langmuir-Blodgett(LB) films, which is a precursor of polyimide(PI). The TSDC measurements of PAAS LB film were performed from room temperature to about $250^{\circ}C$ and the temperature was increased at a rate of $0.2^{\circ}C/s$. This show that this is TSDC peaks at about $70^{\circ}C$ in the arachidic acid LB films, and at about $70^{\circ}C$ and $160^{\circ}C$ in the PAAS LB films. Results of this measurements indicate that one small peak at $70^{\circ}C$ is resulted from a softening of the alkyl group and the large peak at $160^{\circ}C$ is possibly due to dipole moment of C-O group in the PAAS molecule. We have calculated the vertical component of dipole moment of the P AAS LB film out of the TSDC curves. It shows that the dipole moment of PAAS LB film is about -40mD at $70^{\circ}C$ and about 200mD at $160^{\circ}C$ in the first measurement of TSDC. In the second measurement of TSDC of PAAS LB film after cooling down to room temperature, the TSDC peaks are almost disappeared.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 춘계총회 및 연구발표회 초록집
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• pp.40.2-40.2
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• 2004

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 추계총회 및 연구발표회 초록집
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• pp.85.3-85.3
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• 2004

• 한국세라믹학회지
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• 제46권2호
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• pp.155-160
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• 2009

The reliability could be one of the essential properties for multilayer ceramic capacitor (MLCC) using in various electronic devices and the concentration and mobility of oxygen vacancy would play important role in the reliability. To investigate the migration behavior of oxygen vacancies, thermally stimulated depolarization current (TSDC) is adopted. In dielectric material of X5R MLCC, the TSD-Current peak observed around 150$^{\circ}C$ and 200$^{\circ}C$ which represented the migration of oxygen vacancy. Substituting Yttrium for Dysprosium in X5R MLCC showed higher migration activation energy and lower TSD current density.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2207-2210
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• 2010

This paper describes the preparation and study of thermally stimulated discharge conductivity (TSDC) study of cellulose triacetate (CTA) - multiwalled carbon nanotubes (MWNTs) film thermoelectrets. TSDC has been carried out in the temperature range 308 - 503 K and at four different polarizing fields. The conductivity of the polymer blends increased with increase in temperature showing a semi-conducting behavior. The apparent activation energy also showed a pronounced effect with the increase in the content of MWNTs.

• 센서학회지
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• 제29권1호
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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(Mg_1/3Nb_2/3)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.