As the fundamental energy storage components in electronic systems,dielectric capacitors with high power densities were demanded.In this work,the anti-ferroelectric Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3)...As the fundamental energy storage components in electronic systems,dielectric capacitors with high power densities were demanded.In this work,the anti-ferroelectric Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3)(PLSZT)ceramics and thin film capacitor were successfully fabricated by a solid-state reaction route and pulsed laser deposition method,respectively.The ferroelectric,dielectric,energy-storage properties,and temperature stability of anti-ferroelectric PLSZT capacitor were investigated in detail.By compared with the PLSZT ceramic(energy storage density is 1.29 J/cm^(3) with an efficiency of 78.7%under 75 kV/cm),the anti-ferroelectric PLSZT thin film capacitors exhibited the enhanced energy storage density of 52.6 J/cm^(3) with efficiency of 67.7%under an electric field as high as 2068.9 kV/cm,and the enhanced energy-storage temperature stabilities from room temperature(RT)to more than 200℃ were demonstrated,and the oxygen defects mechanism and size effect were discussed.Moreover,the fast charging(~0.05 μs)and discharging(~0.15 μs)time were certified for the anti-ferroelectric PLSZT film capacitor.These findings broaden the horizon for PLSZT anti-ferroelectrics in high energy storage properties and show promising for manufacturing pulse power capacitor.展开更多
Analytical models are presented for a negative capacitance double-gate tunnel field-effect transistor（NC DG TFET） with a ferroelectric gate dielectric in this paper. The model accurately calculates the channel poten...Analytical models are presented for a negative capacitance double-gate tunnel field-effect transistor（NC DG TFET） with a ferroelectric gate dielectric in this paper. The model accurately calculates the channel potential profile by solving the Poisson equation with the Landau-Khalatnikov（LK） equation. Moreover, the effects of the channel mobile charges on the potential are also taken into account. We also analyze the dependences of the channel potential and the on-state current on the device parameters by changing the thickness of ferroelectric layer,ferroelectric material and also verify the simulation results accord with commercial TCAD. The results show that the device can obtain better characteristics when the thickness of the ferroelectric layer is larger as it can reduce the shortest tunneling length.展开更多
基于Swartz and Shrout的二次合成法,采用改进的两步法,将部分原料预合成,一次烧结合成具有100%钙钛矿结构的75Pb(Zn_(1/3)Nb_(2/3))O_3-10PbTiO_3-15BaTiO_3固溶体陶瓷。首先一次性称量PbO,然后和ZnNb_2O_6混合,在660～800℃预合成,将...基于Swartz and Shrout的二次合成法,采用改进的两步法,将部分原料预合成,一次烧结合成具有100%钙钛矿结构的75Pb(Zn_(1/3)Nb_(2/3))O_3-10PbTiO_3-15BaTiO_3固溶体陶瓷。首先一次性称量PbO,然后和ZnNb_2O_6混合,在660～800℃预合成,将预合成产物粉碎后再与TiO_2和BaCO_3按化学计量称量,充分混合后,在1060～1140℃保温1～2h烧结成陶瓷试样。实验结果表明:改进的两步法工艺能够将预合成温度降为660℃,烧结温度能被拓宽到80℃获得100%钙钛矿结构的固溶体陶瓷。不同于传统的预合成和烧结,改进的两步法工艺简单、有效,在预合成阶段没有形成钙钛矿相,烧结阶段陶瓷的成瓷和致密化同时进行,完成了中间相向钙钛矿相的转变,获得了介电性能优良的陶瓷试样。展开更多
In ferroelectric liquid crystals, phase transitions can be induced by an electric field. The current constant method allows these transition to be quickly localized and thus the（E, T） phase diagram of the studied pr...In ferroelectric liquid crystals, phase transitions can be induced by an electric field. The current constant method allows these transition to be quickly localized and thus the（E, T） phase diagram of the studied product can be obtained.In this work, we make a slight modification to the measurement principles based on this method. This modification allows the characteristic parameters of ferroelectric liquid crystal to be quantitatively measured. The use of a current square signal highlights a phenomenon of ferroelectric hysteresis with remnant polarization at null field, which points out an effect of memory in this compound.展开更多
After annealing the solution cast P（VDF-TrFE） films at elevated temperatures, which were synthesized via a full hydrogenation process from P（VDF-CTFE） with a composition of VDF/TrFE = 80/20（mol%）, a series of P...After annealing the solution cast P（VDF-TrFE） films at elevated temperatures, which were synthesized via a full hydrogenation process from P（VDF-CTFE） with a composition of VDF/TrFE = 80/20（mol%）, a series of P（VDF-TrFE） films were fabricated in present work. The crystalline and ferroelectric phases of the films were carefully characterized and their dielectric, ferroelectric and piezoelectric properties were systematically investigated. The improved crystalline and ferroelectric phases in the films induced by annealing at elevated temperatures are responsible for the significant improved electric properties of the films. The optimized annealing temperature is found to be 130 ℃ and the best performance including the highest dielectric constant of 12.5 at 1 kHz, the largest maximum polarization of 11.21 μC/cm^2 and remnant polarization of 7.22 μC/cm^2, the lowest coercive electric field of 56 MV/m, and the highest piezoelectric coefficient of -25 pC/N is observed.展开更多
研究了钡离子 A 位固溶铌镁酸铝(PMN)基多晶体的弛豫特性及其表征方法。实验发现,钡离子的 A 位固溶,增强丁 Pb(Mg,Nb,zr,Ti)O_3(简称 PMNZT)多晶体的相变弛豫程度,提高了介电系数温度稳定性。对于 PMNZT-BT 多晶体,随着 PT/PZ 摩尔数...研究了钡离子 A 位固溶铌镁酸铝(PMN)基多晶体的弛豫特性及其表征方法。实验发现,钡离子的 A 位固溶,增强丁 Pb(Mg,Nb,zr,Ti)O_3(简称 PMNZT)多晶体的相变弛豫程度,提高了介电系数温度稳定性。对于 PMNZT-BT 多晶体,随着 PT/PZ 摩尔数的增加,材料弛豫程度减小。结果表明,Pb(Mg,Nb,zr,Ti)O_3-BT 的介电系数温度关系不同程度地偏离“二次方律:(1/K-1/K_m)=(T-Tecav)~2/2δ~2,而服从经验规律:“(1/K-1/K_n)=C^(-1) (T-TC(?)~γ”。随着钡离子 A 位固溶量的增加,材料弛豫程度越来越大,介电系数温度关系偏离“二次方律”的程度越来越小,临界指数 y 越来越接近于2。与△T_(?)一样,γ值可用于表征材料的相变弛豫程度及介电系数温度稳定性。展开更多
对 Pb(Fe_(1/2)/Nb_(1/2))O_3铁电陶瓷进行了 B 位离子部分取代和改变 Fe/Nb 比对介电性能、介电弛豫性能影响的研究,发现当它的 B 位 B_1、B_2离子比偏离于1:1时,其 K_(max)的频率弥散变明显(即△T_(0.1-100kHz)>0°),这可能是...对 Pb(Fe_(1/2)/Nb_(1/2))O_3铁电陶瓷进行了 B 位离子部分取代和改变 Fe/Nb 比对介电性能、介电弛豫性能影响的研究,发现当它的 B 位 B_1、B_2离子比偏离于1:1时,其 K_(max)的频率弥散变明显(即△T_(0.1-100kHz)>0°),这可能是在有序-无序基本弛豫极化基础上产生了附加的空间电荷弛豫极化,它对弛豫铁电体的介电弛豫性质起着一定贡献。展开更多
Ba1-xSrxTiO3 ceramics, doped with B2O3-Li2O glasses have been fabricated via a traditional ceramic process at a low sintering temperature of 900 ℃ using liquid-phase sintering aids. The microstructures and di- electr...Ba1-xSrxTiO3 ceramics, doped with B2O3-Li2O glasses have been fabricated via a traditional ceramic process at a low sintering temperature of 900 ℃ using liquid-phase sintering aids. The microstructures and di- electric properties of B2O3-Li2O glasses doped Ba1-xSrxTiO3 ceramics have been investigated systemat- ically. The temperature dependence dielectric constant and loss reveals that B2O3-Li2O glasses doped Ba1-xSrxTiO3 ceramics have di？usion phase transformation characteristics. For 5 wt% B2O3-Li2O glasses doped Ba0.55Sr0.45TiO3 composites, the tunability is 15.4% under a dc-applied electric field of 30 kV/cm at 10 kHz; the dielectric loss can be controlled about 0.0025; and the Q value is 286. These composite ceramics sintered at low temperature with suitable dielectric constant, low dielectric loss, relatively high tunability and high Q value are promising candidates for multilayer low-temperature co-fired ceramics （LTCC） and potential microwave tunable devices applications.展开更多
基金financially supported by National Natural Science Foundation of China(NSFC)(Grant Nos.51702055,62073084,11904056,and 51604087)the Guangdong Provincial Natural Science Foundation of China(Grant No.2016A030313718)+1 种基金the Science and Technology Program of Guangdong Province of China(Grant Nos.2016A010104018 and 2017A010104022)Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(Climbing Program Special Funds,Grant No.pdjh2020a0174,pdjh2019a0147).
文摘As the fundamental energy storage components in electronic systems,dielectric capacitors with high power densities were demanded.In this work,the anti-ferroelectric Pb_(0.89)La_(0.06)Sr_(0.05)(Zr_(0.95)Ti_(0.05))O_(3)(PLSZT)ceramics and thin film capacitor were successfully fabricated by a solid-state reaction route and pulsed laser deposition method,respectively.The ferroelectric,dielectric,energy-storage properties,and temperature stability of anti-ferroelectric PLSZT capacitor were investigated in detail.By compared with the PLSZT ceramic(energy storage density is 1.29 J/cm^(3) with an efficiency of 78.7%under 75 kV/cm),the anti-ferroelectric PLSZT thin film capacitors exhibited the enhanced energy storage density of 52.6 J/cm^(3) with efficiency of 67.7%under an electric field as high as 2068.9 kV/cm,and the enhanced energy-storage temperature stabilities from room temperature(RT)to more than 200℃ were demonstrated,and the oxygen defects mechanism and size effect were discussed.Moreover,the fast charging(~0.05 μs)and discharging(~0.15 μs)time were certified for the anti-ferroelectric PLSZT film capacitor.These findings broaden the horizon for PLSZT anti-ferroelectrics in high energy storage properties and show promising for manufacturing pulse power capacitor.
基金Project supported by the University Natural Science Research Key Project of Anhui Province(No.KJ2017A502)the Talents Project of Anhui Science and Technology University(No.DQYJ201603)the Excellent Talents Supported Project of Colleges and Universities(No.gxyq2018048)
文摘Analytical models are presented for a negative capacitance double-gate tunnel field-effect transistor（NC DG TFET） with a ferroelectric gate dielectric in this paper. The model accurately calculates the channel potential profile by solving the Poisson equation with the Landau-Khalatnikov（LK） equation. Moreover, the effects of the channel mobile charges on the potential are also taken into account. We also analyze the dependences of the channel potential and the on-state current on the device parameters by changing the thickness of ferroelectric layer,ferroelectric material and also verify the simulation results accord with commercial TCAD. The results show that the device can obtain better characteristics when the thickness of the ferroelectric layer is larger as it can reduce the shortest tunneling length.
文摘基于Swartz and Shrout的二次合成法,采用改进的两步法,将部分原料预合成,一次烧结合成具有100%钙钛矿结构的75Pb(Zn_(1/3)Nb_(2/3))O_3-10PbTiO_3-15BaTiO_3固溶体陶瓷。首先一次性称量PbO,然后和ZnNb_2O_6混合,在660～800℃预合成,将预合成产物粉碎后再与TiO_2和BaCO_3按化学计量称量,充分混合后,在1060～1140℃保温1～2h烧结成陶瓷试样。实验结果表明:改进的两步法工艺能够将预合成温度降为660℃,烧结温度能被拓宽到80℃获得100%钙钛矿结构的固溶体陶瓷。不同于传统的预合成和烧结,改进的两步法工艺简单、有效,在预合成阶段没有形成钙钛矿相,烧结阶段陶瓷的成瓷和致密化同时进行,完成了中间相向钙钛矿相的转变,获得了介电性能优良的陶瓷试样。
文摘In ferroelectric liquid crystals, phase transitions can be induced by an electric field. The current constant method allows these transition to be quickly localized and thus the（E, T） phase diagram of the studied product can be obtained.In this work, we make a slight modification to the measurement principles based on this method. This modification allows the characteristic parameters of ferroelectric liquid crystal to be quantitatively measured. The use of a current square signal highlights a phenomenon of ferroelectric hysteresis with remnant polarization at null field, which points out an effect of memory in this compound.
基金supported by the National Natural Science Foundation of China(Nos.5110311550903065 and 51573146)+3 种基金Fundamental Research Funds for the Central Universities(Nos.XJJ2013075 and cxtd2015003)International Science & Technology Cooperation Program of China(No.2013DFR50470)Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2013JZ003 and 2015JZ009)National Basic Research Program of China 973(No.6132620101)
文摘After annealing the solution cast P（VDF-TrFE） films at elevated temperatures, which were synthesized via a full hydrogenation process from P（VDF-CTFE） with a composition of VDF/TrFE = 80/20（mol%）, a series of P（VDF-TrFE） films were fabricated in present work. The crystalline and ferroelectric phases of the films were carefully characterized and their dielectric, ferroelectric and piezoelectric properties were systematically investigated. The improved crystalline and ferroelectric phases in the films induced by annealing at elevated temperatures are responsible for the significant improved electric properties of the films. The optimized annealing temperature is found to be 130 ℃ and the best performance including the highest dielectric constant of 12.5 at 1 kHz, the largest maximum polarization of 11.21 μC/cm^2 and remnant polarization of 7.22 μC/cm^2, the lowest coercive electric field of 56 MV/m, and the highest piezoelectric coefficient of -25 pC/N is observed.
文摘研究了钡离子 A 位固溶铌镁酸铝(PMN)基多晶体的弛豫特性及其表征方法。实验发现,钡离子的 A 位固溶,增强丁 Pb(Mg,Nb,zr,Ti)O_3(简称 PMNZT)多晶体的相变弛豫程度,提高了介电系数温度稳定性。对于 PMNZT-BT 多晶体,随着 PT/PZ 摩尔数的增加,材料弛豫程度减小。结果表明,Pb(Mg,Nb,zr,Ti)O_3-BT 的介电系数温度关系不同程度地偏离“二次方律:(1/K-1/K_m)=(T-Tecav)~2/2δ~2,而服从经验规律:“(1/K-1/K_n)=C^(-1) (T-TC(?)~γ”。随着钡离子 A 位固溶量的增加,材料弛豫程度越来越大,介电系数温度关系偏离“二次方律”的程度越来越小,临界指数 y 越来越接近于2。与△T_(?)一样,γ值可用于表征材料的相变弛豫程度及介电系数温度稳定性。
文摘对 Pb(Fe_(1/2)/Nb_(1/2))O_3铁电陶瓷进行了 B 位离子部分取代和改变 Fe/Nb 比对介电性能、介电弛豫性能影响的研究,发现当它的 B 位 B_1、B_2离子比偏离于1:1时,其 K_(max)的频率弥散变明显(即△T_(0.1-100kHz)>0°),这可能是在有序-无序基本弛豫极化基础上产生了附加的空间电荷弛豫极化,它对弛豫铁电体的介电弛豫性质起着一定贡献。
基金support from Functional Materials Research Laboratory, Tongji University, Chinathe Ministry of Sciences and Technology of China through 973-project under Grant No.2009CB623302+1 种基金the National Natural Science Foundation of China under Grant No. 51175483Program for the Outstanding Innovative Teams of High Learning Institutions of Shanxi
文摘Ba1-xSrxTiO3 ceramics, doped with B2O3-Li2O glasses have been fabricated via a traditional ceramic process at a low sintering temperature of 900 ℃ using liquid-phase sintering aids. The microstructures and di- electric properties of B2O3-Li2O glasses doped Ba1-xSrxTiO3 ceramics have been investigated systemat- ically. The temperature dependence dielectric constant and loss reveals that B2O3-Li2O glasses doped Ba1-xSrxTiO3 ceramics have di？usion phase transformation characteristics. For 5 wt% B2O3-Li2O glasses doped Ba0.55Sr0.45TiO3 composites, the tunability is 15.4% under a dc-applied electric field of 30 kV/cm at 10 kHz; the dielectric loss can be controlled about 0.0025; and the Q value is 286. These composite ceramics sintered at low temperature with suitable dielectric constant, low dielectric loss, relatively high tunability and high Q value are promising candidates for multilayer low-temperature co-fired ceramics （LTCC） and potential microwave tunable devices applications.
