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按x=0.00,0.10,0.25,0.50,0.75和1.00,采用固相烧结工艺,制备了不同La掺杂量的SrBi4-xLaxTi4O15的陶瓷样品. 用x射线衍射对其微结构进行了分析,并测量了铁电、介电性能.结果发现,La掺杂未改变SrBi4Ti 4O15的晶体结构.随掺杂量的增加,样品的矫顽场(Ec)下降,剩余极化(2P关键词:
4-xLaxTi4O15')" href="#">SrBi4-xLaxTi4O15
La掺杂
铁电性能
相变温度
弛豫铁电 相似文献
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The pure Cr2O3 coated Li4Ti5O12 microspheres were prepared by a facile and cheap solutionbased method with basic chromium(III) nitrate solution (pH=11.9). And their Li-storage properties were investigated as anode materials for lithium rechargeable batteries. The pure Cr2O3 works as an adhesive interface to strengthen the connections between Li4Ti5O12 particles, providing more electric conduction channels, and reduce the inter-particle resistance. Moreover, LixCr2O3, formed by the lithiation of Cr2O3, can further stabilize Li7Ti5O12 with high electric conductivity on the surface of particles. While in the acid chromium solution (pH=3.2) modification, besides Cr2O3, Li2CrO4 and TiO2 phases were also found in the final product. Li2CrO4 is toxic and the presence of TiO2 is not welcome to improve the electrochemical performance of Li4Ti5O12 microspheres. The reversible capacity of 1% Cr2O3-coated sample with the basic chromium solution modification was 180 mAh/g at 0.1 C, and 134 mAh/g at 10 C. Moreover, it was even as high as 127 mAh/g at 5 C after 600 cycles. At-20℃, its reversible specific capacity was still as high as 118 mAh/g. 相似文献
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本文合成了系列Bi2Ti4-xTexO11样品,拉曼光谱及X射线衍射谱表明该体系的相转化边界发生在x=0.5处,Bi2Te4O11的压致结构相变的压力为8.2GPa。本文结果证实了我们过去对Bi2Ti4O11相变提出的机制 相似文献
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通过原子环境计算方法分析了正交相SrBi4Ti4O15晶体内的键络结构、各原子的空间配位数及局域团簇结构. 在此基础上, 结合晶体分解理论将SrBi4Ti4O15晶体分解为多个二元赝晶体, 根据化学键介电理论计算得到各赝晶体所对应化学键的有效价电子密度、离子性等化学键性质. 通过键偶极矩建立了铁电体自发极化强度与化学键性质之间的关系, 求得正交相SrBi4Ti4O15沿a轴方向的自发极化强度为28.03 μC/cm2, 与实验结果和其他理论计算值符合较好. 相似文献
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在常温下,对La掺杂共生结构铁电陶瓷Bi_4-xLa_xTi_3O_12-SrBi_4-yLayTi_4O_15[BLT-SBLT(x+y),x+y= 0.00, 0.25,0.50,0.75,1.00,1.25,1.50]进行了拉曼光谱研究.结果表明,在掺杂量低于0.50时,La只取代类钙钛矿层中的Bi,当掺杂 量高于0.50后,部分La开始进入(Bi_2O_2)^2+层. La取代(Bi_2O_2)^2+层中的部分Bi以后,(Bi_2O_2)^2+层结构发生变化 ,原有的绝缘层和空间电荷库的作用减弱,导致材料剩余极化下降. La掺杂量增至1.50时,样品出现弛豫铁电性,这与30cm^-1以下模的软化相对应,说明La掺杂可引起材料 的结构相变.
关键词:
Bi4-xLaxTi3O12-SrBi4Ti4O15
La掺杂
声子模
拉曼频移 相似文献
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溶胶凝胶法制备了Na0.5Bi0.5Ti1-xMnxO3(x=0,0.02,0.04)陶瓷样品,X射线衍射(XRD)分析表明陶瓷样品均形成了单一的钙钛矿(ABO3)型结构且没有杂质相的形成.随着Mn含量的增加,XRD峰向高角度方向移动,表明Mn离子进入Na0.5Bi0.5TiO3晶格.掺杂样品均表现出室温铁磁性和铁电性.磁测量表明样品中存在复杂的磁相互作用,包括铁磁,反铁磁和顺磁相互作用.以上结果表明,通过Mn的掺杂可以使铁电材料Na0.5Bi0.5TiO3转变为多铁材料. 相似文献
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本文用差热分析和X射线衍射等方法研究了BaO-Na2O-B2O3三元系的两个截面:BaB2O4-Na2B2O4和BaB2O4-Na2O赝二元系的相平衡关系。BaB2O4-Na2B2O4属共晶体系,其共晶温度为826±3℃。在BaB2O4-Na2O体系中发现一个新化合物BaB2O4·Na2O,该化合物在846±3℃同成分熔化。BaB2O4·Na2O对BaB2O4和Na2O均为共晶体系,其共晶温度分别为755±3℃和573±3℃。并根据所得的结果,分别以15mol%Na2O和13mol%Na2B2O4为助熔剂,用提拉法培养出2×4×6mm3和2×4×8mm3的低温相BaB2O4单晶体。
关键词: 相似文献
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We have observed the anomalous temperature dependence of the phonon modes in the Raman spectra of Bi2Ti4O11 and the modified Bi2Ti4O11 with the dopant of PbO. The square of the lowest mode frequency in both substances decreases linearly with increasing temperature, while the damping constant increases reaching a peak value at the transition temperature. The mode frequency, however, does not tend to zero but stays finite and the damping constant decreases above the transition temperature. The mode is Raman-active both above and below the transition temperature. 相似文献
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本文通过传统的固相反应法制备了R型六角铁氧体BaFe4-xTi2+xO11 (x= 0, 0.25, 0.5, 0.75, 1), 并且对它的原子价态以及磁性行为进行了研究. X 射线光电子能谱(XPS)结果显示了随着掺杂含量的增加, 体系中Fe3+离子逐渐减少而Fe2+离子逐渐增加. 由于具有非对称结构的阻挫晶格中存在各种关联作用的竞争, 使得BaFe4-xTi2+xO11体系表现出了复杂的磁有序行为, 在T1~250 K和T2~83 K两处存在磁转变. 对这一系列掺杂样品, 在相变温度T1之上表现顺磁行为, 而在相变温度T2前后的磁化强度都表现出低场下随磁场的增加快速增加, 高场下则线性变化且在5×104 Oe时还未达到饱和的行为, 表明这一系列掺杂样品是典型的倾斜反铁磁态(canted antiferromagnetic) 或者亚铁磁态. 相似文献
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A. I. Burkhanov Yu. V. Kochergin K. Bormanis A. Kalvane M. Dambekalne 《Physics of the Solid State》2009,51(7):1475-1477
The influence of the prehistory on the electrical properties of layered ferroelectrics is investigated. It is established
that the heating of short-circuited samples of the nonpolarized ceramic material Na0.5Bi8.5Ti2Nb4O27 leads to the appearance of maxima of the current at temperatures below the Curie point only in the case of preliminary ageing
of the samples.
Original Russian Text ? A.I. Burkhanov, Yu.V. Kochergin, K. Bormanis, A. Kalvane, M. Dambekalne, 2009, published in Fizika
Tverdogo Tela, 2009, Vol. 51, No. 7, pp. 1393–1394. 相似文献
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Raman spectra of ceramic Sr2Bi4Ti5O18 (SBTi5) are reported to consist of four different Raman bands. Temperature-dependent spectra reveal the relationship between the lattice vibration and the material's structure. There appears a relatively large change in structure of the material at about 273K, The anharmonic potential of the material has a great influence on its phonon mode full width at half maximum (FWHM), which can be expressed by a function of temperature. Theoretical fittings of the FWHMs for the two modes at around 312 cm^-1 and 464cm^-1 indicate that the latter phonon mode is more anharmonic than the former one. 相似文献
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用衍射仪和Guinier聚焦相机收集了含秘层状结构铁电体PbBi4Ti4O15SrBi4Ti4O15的X射线粉末衍射图谱(Cu Ka),给出了d值大1.13?的88和76条衍射线的衍射数据和指标。它们都属正交晶系,空间群Bb21m(C2v12),点阵常数和X射线理论密度为PbBi4Ti4O15α=5.431?,b=5.459?,c=41.36?; z=4;Dx=7.986g/cm3.SrBi4Ti4O15:α=5.428?,b=5.438?,c=40.94?;Z=4;Dx=7.447g/cm3. 相似文献