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1.
金灿  朱骏  毛翔宇  何军辉  陈小兵 《物理学报》2006,55(7):3716-3720
用传统的固相烧结工艺,制备了钼掺杂铁电陶瓷样品SrBi4Ti4O15(SBTi)铁电陶瓷SrBi4-2x/3Ti4-xMoxO15(x=0.00,0.003,0.012,0.03,0.06,0.09).X射线衍射的结果表明,样品均为单一的层状钙钛矿结构相,Mo掺杂未改变SBTi的晶体结构.通过扫描电子显微镜观测发现,样品晶粒为片状,随掺杂量的增加,晶粒逐 关键词: 4Ti4O15')" href="#">SrBi4Ti4O15 Mo掺杂 剩余极化 居里温度  相似文献   

2.
La掺杂SrBi4Ti4O15铁电材料性能研究   总被引:3,自引:0,他引:3       下载免费PDF全文
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   

3.
单丹  朱珺钏  金灿  陈小兵 《物理学报》2009,58(10):7235-7240
采用了传统的固相烧结工艺,制备了不同Zr和Hf掺杂量的SrBi4Ti4-xZrxO15x=000,003, 006,010,020)和SrBi4Ti4-xHfxO15x=000,0005, 0015,0030,0060)的陶瓷 关键词: 4Ti4-xZrxO15')" href="#">SrBi4Ti4-xZrxO15 4Ti4-xHfxO15')" href="#">SrBi4Ti4-xHfxO15 铁电性能 介电性能  相似文献   

4.
肖小红  李世春 《物理学报》2016,65(6):63101-063101
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   

5.
王华  任明放 《物理学报》2007,56(12):7315-7319
采用溶胶凝胶工艺在p-Si衬底上制备了SrBi2Ta2O9/Bi4Ti3O12复合铁电薄膜. 研究了SrBi2Ta2O9/Bi4Ti3O12复合薄膜的微观结构与生长行为、铁电性能和疲劳特性. 研究表明: Si衬底Bi4Ti< 关键词: 2Ta2O9')" href="#">SrBi2Ta2O9 4Ti3O12')" href="#">Bi4Ti3O12 复合铁电薄膜 溶胶凝胶工艺  相似文献   

6.
采用溶胶-凝胶工艺成功制备出BaBi4Ti4O15微细粉料,并利用此微粉烧结出成瓷良好的BaBi4Ti4O15陶瓷.研究了BaBi4Ti4O15陶瓷的铁电 顺电相 变,测定了BaBi4Ti4O15的介 电特性和饱和状态下的铁电特性.所作测量表明B 关键词: 铁电性 介电性 晶格结构 溶胶 凝胶法  相似文献   

7.
朱骏  卢网平  刘秋朝  毛翔宇  惠荣  陈小兵 《物理学报》2003,52(10):2627-2631
采用固相烧结工艺,制备了不同La掺杂量(x=0.00,0.25,0.50,0.75,1.00,1.25和1.50) 的(Bi, La)4Ti3O12-Sr(Bi, La)4Ti4O15 (SrBi8-xLaxT i7O27)共生结构铁电陶瓷样品.用x射线衍射对其进行微结构分析 ,并测量铁 关键词: 4Ti3O12-SrBi4Ti4O15')" href="#">Bi4Ti3O12-SrBi4Ti4O15 La掺杂 铁电性能 居里温度 弛豫铁电  相似文献   

8.
陈延彬  张帆  张伦勇  周健  张善涛  陈延峰 《物理学报》2015,64(9):97502-097502
基于纳米尺寸下复合铁电材料和反铁磁性材料是一个探索多铁性材料有效的方法. 利用激光脉冲沉积制备出LaFeO3-YMnO3人工超晶格和掺入不同层LaFeO3, BiFeO3的Bi4Ti3O12的外延薄膜. 通过系统的X射线衍射、透射电子显微术、扫描透射电子显微术下的能量损失谱表征证明这些样品具有原子尺寸上清晰的界面和完整的层状结构. 磁性测试证明这些材料具有亚铁磁性. 特别是在0.5和1.5LaFeO3-Bi4Ti3O12中的亚铁磁性甚至能保持到室温. 就铁电性而言, 铁电性测试显示出LaFeO3-YMnO3和插入BiFeO3的Bi4Ti3O12样品中存在较大的漏电流, 而在0.5LaFeO3-Bi4Ti3O12样品中存在铁电性. 因此在0.5LaFeO3-Bi4Ti3O12中能够实现亚铁磁和铁电共存. 其次发现当掺入多层的钙钛矿(3层SrTiO3或2.5层LaFeO3)后, Bi4Ti3O12 的层状结构将出现结构失稳现象. 这些工作对于利用纳米复合开发新颖多铁性提供一些实例.  相似文献   

9.
CaCu3Ti4O12块材和薄膜的巨介电常数   总被引:4,自引:2,他引:2       下载免费PDF全文
赵彦立  焦正宽  曹光旱 《物理学报》2003,52(6):1500-1504
用固相反应法和脉冲激光沉积(PLD)制备了CaCu3Ti4O12块材和薄膜,获得了相对介电常数ε′(1kHz,300K)高于14000的介电特性,是目前该体系最好的结果.报道了(00l)取向高质量CaCu3Ti4O12外延薄膜及其介电性质.C aCu3Ti4O12相对介电常数ε′在100—300K温度范围 内 关键词: 3Ti4O12')" href="#">CaCu3Ti4O12 巨介电常数 PLD  相似文献   

10.
通过固相反应烧结法成功制备了层状钙钛矿La1.3Sr1.7Mn2-xCuxO7多晶,主要研究了其磁电特性.结果表明,样品为Sr3Ti2O7型钙钛矿结构.随着温度的降低,其磁性经历了一个很复杂的转变过程.当x=0时,在T*=231K出现二维短程铁磁有序,在< 关键词: 层状钙钛矿 磁性 电特性  相似文献   

11.
Ceramics with the nominal composition of SrBi4−xLaxTi4O15 have been prepared within the range of 0≤x≤1.8, and the dielectric properties are investigated. Single phase SrBi4−xLaxTi4O15 solid solution exists until the secondary phase of La2/3TiO3 appears at x=1.6. The Curie temperature is 520 °C for pure SrBi4Ti4O15, and it shifts to low temperature with increasing x, which is due to the smaller structural distortion caused by La3+ substitution. In addition, the dielectric constant anomaly is suppressed with the substitution. No dielectric relaxation behavior is observed. When x≥1.2, the paraelectric state is attained in the present ceramics. La3+ substitution effects on the SrBi4Ti4O15 ceramics are also compared with the previous work on Bi4−xLaxTi3O12.  相似文献   

12.
吴云翼  王晓慧  李龙土 《中国物理 B》2010,19(3):37701-037701
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   

13.
Magnetic interaction in Mg, Ti, Nb doped manganites   总被引:4,自引:0,他引:4  
An effect of Mn substitution with Me=Mg2+, Ti4+, Nb5+ in manganites has been investigated by preparing La0.7Sr0.3(Mn1-xMex)O3 and La1-xSrx(Mn1 - x/2Nbx/2)O3 series. It was established that substitution of manganese with magnesium up to x = 0.16 leads to a collapse of a long-range ferromagnetic order whereas La0.7Sr0.3(Mn 3 + 0.85Nb 5 + 0.15)O3 is ferromagnet with T C = 123 K and exhibits a large magnetoresistance below Curie point despite an absence of four-valent manganese. Hypothetical magnetic phase diagrams are constructed for La0.7Sr0.3(Mn1-xMex)O3 and La1-xSrx(Mn1 - x/2Nbx/2)O3. Our results show that Mn3+-O-Mn3+ exchange interaction is ferromagnetic in the orbitally disordered manganites as well as an increase of Mn4+ content above 50% from a total amount of manganese ions leads to formation of a spin glass state due to a competition between antiferromagnetic Mn4+-O-Mn4+ and ferromagnetic Mn3+-O-Mn4+(Mn3+) superexchange interactions. Received 24 January 2002 Published online 9 July 2002  相似文献   

14.
We report X-ray diffraction, resistivity and Mössbauer studies on several substituted 2201 Bi cuprates, Bi2Sr2Cu1?xFexOy(O≤x≤1) and Bi2Sr1.6La0.4Cu1?xFexOy and Bi1.6Pb0.4Sr1.6La0.4Cu1?xFexOy (O≤x≤0.04). The first series is not superconducting and a new phase appears for x=1. For La substituted samples, Tc increases up to 35K and decreases strongly with x. All Mössbauer spectra were fitted well with four quadrupole doublets, with relative population depending on samples.  相似文献   

15.
孟进芳  邹广田  崔启良  赵永年 《物理学报》1994,43(10):1739-1744
合成了LaxBi2-xTi411系列样品,并完成了它们的喇曼光谱和x射线衍射测量;结果表明,该体系在X=1.2经历了一次相变,且相变与最低频声子模随X的变化有关。La0.2Bi1.8·Ti411的相变温度为200℃。初步获得La2Ti411的结构为正交结构。 关键词:  相似文献   

16.
In this study, Bi4Ti3O12–SrBi4Ti4O15 (BIT–SBTi) intergrowth ferroelectric ceramics was synthesized by a modified oxalate route. The phase formation behaviour, structure, morphology and electrical properties of the intergrowth ceramics were also investigated. The phase formation takes place through intermediate phases like SrBi2O4 and Bi12TiO20. The precursor mostly changes to Bi4Ti3O12 at 600°C and to BIT–SBTi intergrowth at 800°C. Rietveld analysis of the X-ray diffraction pattern showed that the structure of the intergrowth compound was orthorhombic with lattice parameters a = 5.4408(3), b = 5.4505(1) and c = 74.0851(4) Å. The intergrowth ferroelectrics showed a phase transition at 610°C and a frequency-stable permittivity and dielectric loss behaviour. The intergrowth ferroelectrics also showed a larger 2Pr than their constituents BIT and SBTi.  相似文献   

17.
杨洋  刘玉龙  朱恪  张丽艳  马树元  刘洁  蒋毅坚 《中国物理 B》2010,19(3):37802-037802
This paper reports that La-doped BiFeO 3(Bi1-x La x FeO3,x = 0,0.1,0.2,0.3,0.6,0.8 and 1.0) were studied by using micro-Raman spectroscopy and x-ray diffraction(XRD).The XRD patterns indicate that the structure of Bi1-xLaxFeO 3 changes from rhombohedral BiFeO3 to orthorhombic LaFeO3.The results of Raman spectroscopy show good agreement with the XRD results.Strikingly,the phonon peak at around 610 cm-1 and the two-phonon peaks in the high frequency range exist in all compounds and enhance with increasing La substitution.The increasing intensity of the 610 cm-1 peak is attributed to the changes in the FeO 6 octahedron during the rhombohedral-orthorhombic phase transition.The enhancements of the two-phonon peaks are associated with the breakdown of the cycloid spin configuration with the appearance of the orthorhombic structure.These results indicate the existence of strong spin-phonon coupling in Bi1-xLax FeO3,which may provide useful information for understanding the effects of La content on the structural and magnetic properties of Bi1-xLaxFeO3.  相似文献   

18.
林雪  关庆丰  刘洋  李海波 《中国物理 B》2010,19(10):107701-107701
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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