Advances in ZnO–Bi2O3 based varistors

Li, Jianying; Li, Shengtao; Cheng, Pengfei; Alim, Mohammad A.

doi:10.1007/s10854-015-3093-1

Cited by 38 publications

(14 citation statements)

References 135 publications

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“…82-1101) are detectable, as well. In accordance with other previous reports [16,22], the Bi-rich phases are different in samples quenched at different temperatures. In the samples with elevated quenching temperatures, i.e., samples Q-1200-2h and Q-1000, the Bi-rich phase is mainly observed as δ−Bi2O3 cubic phase (JCPDS card no.…”

Section: Surface Morphology and Phase Compositionsupporting

confidence: 93%

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Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Xie¹,

Wang

2022

Materials

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In this paper, evolution of microstructures, electrical properties and defects of the double Schottky barrier during the sintering process were investigated by quenching ZnO varistor ceramics at different sintering stages. It was found that morphology of the samples changed little when the temperature was below 800 °C. Remarkable enhancement of the Schottky barrier height and electrical properties took place in the temperature range between 600 °C and 800 °C. The Bi-rich intergranular layer changed from β phase to α phase. The interfacial relaxation at depletion/intergranular layers became detectable in the samples. Meanwhile, a distinct relaxation loss peak from electron trapping of interface states was observed instead of two dispersed ones. It indicated that the differences among the Schottky barriers in ZnO varistor ceramics became smaller with the process of sintering, which was also supported by the admittance spectra. In addition, oxygen vacancy was found more sensitive to the sintering process than zinc interstitial. The results could provide guidance for fine manipulating the Schottky barrier and its underlying defect structures by optimizing sintering process.

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Section: Surface Morphology and Phase Compositionsupporting

confidence: 93%

“…The Bi-rich intergranular phase acts as a pass way for oxygen transport. DSBs were formed during the cooling process when sufficient oxygen was absorbed at GBs [16,21,22]. Currently, the microstructural evolution of ZnO varistor ceramics during the sintering process is relatively clear.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Xie¹,

Wang

2022

Materials

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“…Оксиды со структурой перовскита, имеющие общую формулу ABO 3 , уже давно являются предметом интенсивных исследований благодаря своим уникальным свойствам -от сегнетоэлектричества и пьезоэлектричества до колоссального магнитосопротивления и мультиферроидных свойств [1]. Среди этих оксидов большое значение имеет титанат стронция SrTiO 3 , электрические, оптические, термоэлектрические и сверхпроводящие свойства которого могут быть использованы или уже используются в различных электронных и других устройствах [2][3][4][5][6][7]. Представляют интерес также фотокаталитические и сенсорные свойства легированного SrTiO 3 [8][9][10].…”

Section: Introductionunclassified

О возможности введения примеси железа в узлы A в SrTiO-=SUB=-3-=/SUB=-

Случинская¹,

Лебедев²

2022

Физика Твердого Тела

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The local environment and oxidation state of the Fe impurity in strontium titanate are studied using XAFS spectroscopy. The influence of annealing temperature and deviation from stoichiometry on the possibility of incorporation of the impurity into the A and B sites of the perovskite structure is studied. The results obtained from the X-ray diffraction, XANES spectra, and EXAFS spectra suggest that at high annealing temperature the iron atoms, at least partially (up to 30%), enter the A sites in SrTiO3. The obtained results agree with results of first-principles calculations, according to which the iron at the A site exhibits strong off-centering (the displacement of ~1 Angstrom), similar to that previously established in SrTiO3 samples doped with Mn and Co.

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“…ZnO varistor ceramics with proper addition of a small amount of cations are widely employed in overvoltage protection and surge absorption in electric power systems, because of their excellent non-linear current-voltage characteristic and large energy absorption capability [1][2][3]. Since it was discovered by Matsuoka in 1971, the initial non-linear material SiC was quickly replaced by ZnO and gapless surge arresters became the mainstream of surge arresters [4].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the effects of Co ₂ O ₃ on multiscale defect structures and relevant electrical properties in ZnO varistors

Men

Wang

et al. 2020

High Voltage

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Element doping is an effective method to improve the performance of ZnO varistors. Previous studies mainly focused on the variation of microstructures and Schottky barriers. In this study, the effects of Co dopant on electrical properties are investigated from the aspect of multiscale defect structures, including intrinsic point defects, the heterogeneous interface of depletion/intergranular layers, and interface states at grain boundaries. Combining with analysis of phase composition and energy dispersive spectroscopy, it is found that Co tends to dissolve into ZnO grains when slightly doped. It substitutes Zn 2+ with the same valence and affects little on densities of donors. Segregation of Co at grain boundaries would result in the formation of spinel phase Co(Co 4/3 Sb 2/3)O 4 and transformation of the intergranular phase from α-Bi 2 O 3 to δ-Bi 2 O 3. Meanwhile, densities of point defects are indirectly affected by oxygen ambient during sintering, resulting in abnormal variation of grain resistivity. And interface states are enhanced, leading to improved barriers at grain boundaries. Therefore, reduced leakage current, enhanced grain resistivity, and improved non-linear coefficient in Co-doped ZnO varistor blocks are understood from the underlying multiple defect structures. This presents a potential approach to explore short-term performance and long-term stability of ZnO varistors from the aspect of defect responses.

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Advances in ZnO–Bi2O3 based varistors

Cited by 38 publications

References 135 publications

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

О возможности введения примеси железа в узлы A в SrTiO-=SUB=-3-=/SUB=-

Revisiting the effects of Co ₂ O ₃ on multiscale defect structures and relevant electrical properties in ZnO varistors

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Advances in ZnO–Bi2O3 based varistors

Cited by 38 publications

References 135 publications

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

О возможности введения примеси железа в узлы A в SrTiO-=SUB=-3-=/SUB=-

Revisiting the effects of Co 2 O 3 on multiscale defect structures and relevant electrical properties in ZnO varistors

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Revisiting the effects of Co ₂ O ₃ on multiscale defect structures and relevant electrical properties in ZnO varistors