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采用柠檬酸-硝酸盐法制备了Bi_(6-x)Nd_xFe_(1.4)Ni_(0.6)Ti_3O_(18)(BNFNT-x,x=0.00,0.10,0.20,0.25和0.30)前驱液,再经过干燥、烧结过程制备了单相多晶材料.研究发现,少量Nd掺杂有助于提高样品的铁电性能,BNFNT-0.25样品的铁电性能(2Pr)最大,约达到19.7μC/cm~2.室温下BNFNT-0.20样品磁性能(2Ms)最大约达到4.132 emu/g(1 emu/g=10–3 A·m~2/g).变温介电损耗结果表明Nd掺杂降低了Fe~(3+)和Fe~(2+)间的电子转移或跃迁的激活能.X射线光电子能谱结果表明小量Nd掺杂有助于增强Bi离子稳定性,对改善样品的铁电性能有积极意义. 相似文献
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利用射频磁控溅射技术在LaNiO_3/SiO_2/Si基底上制备了Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3/CoFe_2O_4和Pb(Mg_(1/3)Nb_(2/3))O_3-Pb TiO_3/Co Fe_2O_4/Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3两种复合薄膜.我们采取了三种退火条件对复合薄膜进行退火处理,研究两种复合薄膜的晶体结构、电学和磁学性能.通过对两种复合薄膜的结构的分析,发现两步法退火后得到复合薄膜同时存在纯钙钛矿相和尖晶石相两种结构.铁电性能测试表明,两种复合薄膜均具有较好的铁电性能,其中三层复合薄膜的剩余极化强度Pr最大可以达到14.9μC/cm2,这要归因于多层复合薄膜内部的应力-应变效应和界面耦合效应.在电场强度为80 k V/cm的漏电流密度数量级仅10-5A/cm2,其导电机制在高电场区满足Schottky机制.介频性能测试表明:复合薄膜的介频特性较差,双层复合薄膜的介电性能较好,其介电常数εr为1078,其介电损耗tgδ较大,约为0.43.此外,对复合薄膜的磁滞回线测试表明:两种复合薄膜中均存在磁学性能,且双层结构复合薄膜的铁磁性能较大,其饱和磁化强度Ms为119 emu/cm3,剩余磁化强度Mr达到31.6 emu/cm3,矫顽场Hc为1360 Oe.以上测试结果表明,铁电有序和磁有序可以存在于钙钛矿-尖晶石结构当中,通过多层复合和合适退火方式可以增强其铁电和介电性能. 相似文献
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利用射频磁控溅射技术在LaNiO3/SiO2/Si基底上制备了Pb(Mg1/3Nb2/3)O3-PbTiO3/CoFe2O4和Pb(Mg1/3Nb2/3)O3-PbTiO3/CoFe2O4/Pb(Mg1/3Nb2/3)O3-PbTiO3两种复合薄膜.我们采取了三种退火条件对复合薄膜进行退火处理,研究两种复合薄膜的晶体结构、电学和磁学性能.通过对两种复合薄膜的结构的分析,发现两步法退火后得到复合薄膜同时存在纯钙钛矿相和尖晶石相两种结构.铁电性能测试表明:两种复合薄膜均具有较好的铁电性能,其中三层复合薄膜的剩余极化强度Pr最大可以达到14.9 μC/cm2,这要归因于多层复合薄膜内部的应力-应变效应和界面耦合效应.在电场强度为80kV/cm的漏电流密度数量级仅10-5A/cm2,其导电机制在高电场区满足Schottky机制.介频性能测试表明:复合薄膜的介频特性较差,双层复合薄膜的介电性能较好,其介电常数εr为1078,其介电损耗tgδ较大,约为0.43.此外,对复合薄膜的磁滞回线测试表明:两种复合薄膜中均存在磁学性能,且双层结构复合薄膜的铁磁性能较大,其饱和磁化强度Ms为119 emu/cm3,剩余磁化强度Mr达到31.6 emu/cm3,矫顽场Hc为1360 Oe. 以上测试结果表明,铁电有序和磁有序可以存在于钙钛矿-尖晶石结构当中,通过多层复合和合适退火方式可以增强其铁电和介电性能. 相似文献
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Mn掺杂对多铁性BiFeO_3薄膜铁电性能以及漏电流的影响 总被引:3,自引:0,他引:3
本文利用脉冲激光沉积技术在(LaAlO3)0.3(Sr2AlTaO6)0.7(001)衬底上生长了BiFe1-xMnxO3(x=0~5%)外延薄膜,研究了Mn掺杂对BiFeO3(BFO)薄膜结构、铁电特性和漏电流的影响.XRD和SEM结果表明薄膜具有良好的结晶质量.漏电流测量显示Mn掺杂有效地减小了BFO薄膜的漏电流密度,因而在室温下5%Mn掺杂的BFO薄膜能够获得饱和的电滞回线.XPS分析证明,Mn掺杂改善BFO薄膜性能的可能原因在于其极大地减少了BFO薄膜中的Fe2+离子. 相似文献
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采用水热方法合成Ce1-x(Fe0.5La0.5)xO2-δ固溶体。利用X射线衍射技术(X-ray diffraction tech-nique,XRD)表征样品的相结构,并对固溶体的晶胞参数进行拟合,通过紫外可见漫反射光谱(UV-Vis dif-fraction spectrum)及拉曼光谱(Raman spectrum)表征其电子跃迁性能及由于双离子掺杂所引起的一系列掺杂效应。XRD结果表明,Ce1-x(Fe0.5La0.5)xO2-δ固溶体为CeO2立方萤石结构,当掺杂量增加到x=0.30时出现了微弱的Fe2O3杂相衍射峰;讨论了两种离子在晶格中不同的取代位置。晶胞参数随着掺杂量的增大而逐渐增大,当掺杂量达到x=0.18后保持基本不变。紫外漫反射光谱表明,随着掺杂量的增大,固溶体的带隙吸收边红移,即能隙逐渐减小,Fe离子在CeO2晶格中表现为+3价。Raman光谱F2g振动峰位逐渐向低波数方向移动,同时振动峰逐渐宽化,进一步证明了掺杂离子的影响效应。 相似文献
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通过对(Pb087Ba01La002)(Zr06TixSn04-x)O3(004≤x≤020)固溶体的介电和偏压热释电性质的研究发现,当Ti含量004≤x≤007时,材料是反铁电四方相,而当009≤x≤020时,材料向弛豫型铁电体转化.在温度Ti含量相图中,x=009附近形成了反铁电铁电顺电三相共存点(Ttr).该点的相变温度最底;对于004≤x≤007的反铁电四方相,低温下呈现介电弛豫特征,并可被外电场诱导为亚稳铁电态,温度升高时,亚稳铁电→反铁电相变,反铁电→顺电相变引起两个热释电流峰,偏置电场下峰位和峰强均发生移动,在温度电场相图中也形成了铁电反铁电顺电三相点.从复杂化合物纳米相分离的观点和晶格动力学出发,讨论了相变与电学性能随Ti含量(x)和外电场(E)变化的物理机理.
关键词:
反铁电/弛豫型铁电相界
介电性能
偏压热释电性质
铁电-反铁电-顺电三相点 相似文献
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用固相工艺制备了Bi6Fe2-xCoxTi3O18 (BFCT-x, x=0, 0.2, 0.6, 0.8, 1.0, 1.2, 1.6, 1.8, 和2.0)多铁陶瓷样品, 样品X射线谱分析发现, 随着Co含量的增加, 样品晶格常数出现了先增大后减小的变化. 室温下, BFCT-0.6样品呈现出相对较高的饱和磁化强度, 2Ms约为4.49 emu/g, BFCT-1.0具有最高的剩余磁化强度, 2Mr约为0.89 emu/g. Co含量在0.2 ≤x≤qslant 1.2范围内, 随着Co含量的增加样品顺磁–铁磁相变温度从752 K降至372 K. 小量的Co改善了样品的铁电性能, 当x=0.6时样品样品的铁电性能最佳, 随着含量增大样品铁电性能下降, 但当x >1.2时样品的铁电性能又得到了改善. 相似文献
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La/Mn co-doped Bi4Ti3O12 ceramics,Bi3.25La0.75Ti3-xMnxO12(x=0.02,0.04,0.06,0.08),were prepared by the solid-state reaction method.The influence of manganese substitution for the titanium part in Bi 3.25 La 0.75 Ti 3 O 12 on the sintering behaviour,microstructure,Raman spectra and electrical properties was investigated.The experimental results show that the phase composition of all samples with and without manganese doping,sintered at 1000 ℃,consists of a single phase with a bismuth-layered structure belonging to the crystalline phase Bi4Ti3O12.There is no evidence of any impurity phase,but a small change in crystallographic orientation is observed.The Curie temperature of Bi3.25La0.75Ti3-xMnxO12 ceramics is steadily shifted to lower temperature with increasing Mn-doping content.Moreover,the remnant polarisation(Pr) of Bi3.25La0.75Ti2.92Mn0.08O12 samples increases with Mn-doping content,and the Bi3.25La0.75Ti2.92Mn0.08O12 sample exhibits the largest P r of 16.6 μC/cm 2. 相似文献
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利用Sol-Gel法在Pt/Ti/SiO2/Si衬底上制备出Bi4Ti3O12和Bi3.25La0.75Ti3O12薄膜,研究了La掺杂对Bi4Ti3O12薄膜的晶体结构、铁电性能和疲劳特性的影响,发现La掺杂没有改变Bi4Ti3O12薄膜的基本晶体结构,并且提高了Bi4Ti3O12铁电薄膜的剩余极化值和抗疲劳性能,对La掺杂改善Bi4Ti3O12铁电薄膜性能的机理进行了讨论.
关键词:
铁电性能
4Ti3O12薄膜')" href="#">Bi4Ti3O12薄膜
3.25La0.75Ti3O12薄膜')" href="#">Bi3.25La0.75Ti3O12薄膜
sol-gel法
La掺杂 相似文献
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We present an effective way in this paper to increase the density of lanthanum doped bismuth titanate ceramics, Bi4-xLaxTi3O12 (BLT), thereby significantly improving the performance of the BLT ceramics. Dense BLT ceramicses, Bi4-xLaxTi3O12 (x = 0.25, 0.5, 0.75, 1.0), are prepared by using nanocrystalline powders fabricated by a-gel method and high-pressure technique. The microstructures of the BLT ceramicses prepared separately by conventional-pressure and high-pressure techniques are investigated by using x-ray diffraction and transmission electron microscope. The influence of La-doping on the densification of bismuth titanate ceramics is investigated. The experimental results indicate that the phase compositions of all samples with various lanthanum dopings sintered at 900°C possess layer-structure of Bi4Ti3O12 . The green compacts are pressed under 2.5 GPa, 3.0 GPa, 3.5 GPa and 4.0 GPa, separately. It is found that the density of BLT ceramics is significantly increased due to the decreasing of porosity in the green compacts by high-pressure process. 相似文献
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Co-doped Bi5FeTi3O15 thin films (BFCT-x, Bi5Fe1-xCoxTi3O15) were prepared using a sol—gel technique. XRD patterns confirm their single phase Aurivillius structure, and the corresponding powder Rietveld analysis indicates the change of space group around x=0.12. The magnetic hysteresis loops are obtained and ferromagnetism is therefore confirmed in BFCT-x thin films. The remanent magnetization (Mr) first increases and reaches the maximum value of 0.42 emu/cm3 at x=0.12 due to the possible Fe3+—O—Co3+ ferromagnetic coupling. When x = 0.25, the Mr increases again because of the dominant Fe3+—O—Co3+ ferromagnetic coupling. The remanent polarization (2Pr) of BFCT-0.25 was measured to be as high as 62 μC/cm2, a 75% increase when compared with the non-doped BFCT-0 films. The 2Pr remains almost unchanged after being subjected to 5.2 × 109 read/write cycles. Greatly enhanced ferroelectric properties are considered to be associated with decreased leakage current density. 相似文献
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Jie SuXiaomei Lu Chao ZhangJunting Zhang Hui SunChangcheng Ju Zhijun WangKangli Min Fengzhen HuangJinsong Zhu 《Physica B: Condensed Matter》2012,407(3):485-488
Ho3Fe5O12 ceramics with garnet structure were prepared by the solid-state reaction method. The results revealed the existence of Fe2+ ions have intensive influence on dielectric and magnetic properties of Ho3Fe5O12 ceramics, which could be further confirmed by oxygen treatment. With a magnetic field lower than 10 kOe, the ME coefficient reaches 33 ps m−1 at room temperature. And the ME coupling was further verified by dielectric anomaly near Néel temperature. 相似文献
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Weiwei Ling Huaiwu Zhang Ying He Yang Wu Kai Yang Yuanxun Li Sheng Li 《Journal of magnetism and magnetic materials》2010,322(7):819-823
The Ni-Cu-Zn ferrites with different contents of Bi4Ti3O12 ceramics (1-8 wt%) as sintering additives were prepared by the usual ceramic technology and sintered at 900 °C to adapt to the low temperature co-fired ceramic (LTCC) technology. The magnetic and dielectric properties of the ferrite can be effectively improved with the effect of an appropriate amount of Bi4Ti3O12. For all samples, the ferrite sintered with 2 wt% Bi4Ti3O12 has relatively high density (98.8%) and permeability, while the ferrite with 8 wt% Bi4Ti3O12 has relatively good dielectric properties in a wide frequency range. The influences of Bi4Ti3O12 addition on microstructure, magnetic and dielectric properties of the ferrite have been discussed. 相似文献
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Effects of switching pulse width and stress on properties of Bi3.25La0.75Ti3O12 thin films 下载免费PDF全文
Polycrystalline ferroelectric Bi3.25La0.75Ti3O12 thin films are prepared on Pt/Ti/SiO2/Si substrates by the conventional metalorganic decomposition method.It is observed that with the increase of switching pulse width,the remnant polarisation and the coercive field increase.A wider switching pulse can result in poorer fatigue properties,which comes from more charged defects diffusing to and being trapped on domain walls.On the other hand,when the compressive stress is applied to films,the fatigue properties can be improved.This phenomenon is due to the reorientation of domains under stress. 相似文献