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采用化学共沉淀法制备了不同Ba2+掺杂浓度、 不同煅烧温度的Sr0.8-xBaxEu0.2WO4红色荧光粉. 研究了样品的晶体取向和晶格 畸变对发光性质的影响, 实验结果表明: 合成的Sr0.8-xBaxEu0.2WO4红色荧光粉为四方相, 样品中Eu3+的5D0–7F2跃迁的红光能被近紫外光和蓝光有效激发. 适量的Ba2+离子取代部分的Sr2+提高了Sr0.8Eu0.2WO4荧光粉的发光强度, Ba2+掺杂浓度的改变对基质的晶格参数、晶体对称性和发光性能影响较大, Ba2+的最佳掺杂量为30%. 相似文献
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Sr位Nd掺杂对SrBi$lt;sub$gt;2$lt;/sub$gt;Nb$lt;sub$gt;2$lt;/sub$gt;O$lt;sub$gt;9$lt;/sub$gt;性能的影响及机理研究 下载免费PDF全文
采用传统固相法制备了(Sr1-3x/2Ax/2Ndx)Bi2Nb2O9(x=0,0.05,0.1和0.2)陶瓷,并系统研究了Nd离子取代Sr离子对SrBi2Nb2O9性能的影响及其作用机理.研究结果表明:Sr1-3x/2Ax/2NdxBi2Nb2O9的介电常数和介电损耗随温度变化的行为具有明显的离子松弛极化特征.Nd3+对Sr2+的部分取代,导致Sr1-3x/2Ax/2NdxBi2Nb2O9剩余极化强度Pr稍有下降,但其压电系数d33却有所增加,根据铁电热力学理论,这是Nd3+对Sr2+取代导致材料介电常数增大所致.Sr1-3x/2Ax/2NdxBi2Nb2O9的居里温度(TC)没有随Nd含量的增加而变化,拉曼光谱技术分析表明这是其NbO6八面体畸变程度没有发生变化所致.Nd3+取代Sr2+提高了材料的介电常数εr、压电系数d33、机电耦合系数Kp,同时降低了机械品质因数Qm,但是谐振频率温度系数C值没有改变.
关键词:
压电陶瓷
介电性能
压电性能
拉曼光谱 相似文献
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采用高温固相法制备出Ca1.97-xSrxNb2O7:3%Eu3+(x=0.10,0.50,1.0,1.5,1.97)红色荧光粉,研究了Ca1.97-xSrxNb2O7:3%Eu3+的发光特性及Sr2+的浓度对该荧光粉发光性质的影响。随着Sr2+浓度的改变,Ca2-xSrxNb2O7:Eu3+的XRD呈现不同的相。Ca1.97Nb2O7:3%Eu3+(x=0)的激发光谱中,302 nm附近的强宽带来自于O2-→Eu3+电荷转移跃迁,272 nm附近的肩峰来自于NbO7-6基团的电荷转移跃迁,350~600 nm范围内的锐锋属于Eu3+的特征4f-4f组内跃迁。在398 nm激发下,发射光谱的最强峰位于616 nm,属于Eu3+的5D0→7F2电偶极跃迁,发射出强烈的红光。当Ca2+逐渐被Sr2+取代时,Ca2-xSrxNb2O7:Eu3+的各激发峰的强度先提高后降低,且O2-→Eu3+电荷转移跃迁发生明显红移。少量Sr2+的掺杂可以有效提高Ca2-xSrxNb2O7:Eu3+ 的红光发射强度,当x=0.01时该荧光粉的红光发射达到最强,可以被紫外LED芯片激发。 相似文献
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采用高温固相法在1 350 ℃弱还原气氛下制备了Sr1-xBaxAl2O4 : Eu2+ ,Dy3+ (x=0,0.2,0.4,0.6,0.8,1.0)长余辉材料,并对其微观结构和发光特性进行了分析。X射线衍射结果表明,当钡的掺杂摩尔分数x<0.4时,样品晶体结构为SrAl2O4单斜晶系结构;当x≥0.4时,样品晶体结构为BaAl2O4六角晶系结构;而且随着钡对锶的取代,两种晶体结构的晶格常数都发生了一定程度的膨胀。光致发光测试结果表明,当x从0增大到1.0时,样品发射波长峰值也相应由515 nm逐渐蓝移到494 nm。通过热释光谱测试表明, SrAl2O4结构的样品的热释光峰所对应的温度比BaAl2O4 结构的要高,且对应SrAl2O4结构的样品的余辉时间更长,初始亮度更高。 相似文献
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在超高真空分子束外延(MBE)生长技术中,反射式高能电子衍射仪(RHEED)能实时显示半导体和金属外延生长过程,给出薄膜表面结构和平整度的信息,成为MBE必备的原位表面分 析仪.为了研究氧化物薄膜如高温超导(YBa2Cu3O7) 、铁电薄膜(Sr1-xBax TiO3)及它们的同质和异质外延结构的生长机理,获得高质量的符合各种应用 需要的氧化 物多层薄膜结构,在常规的制备氧化
关键词:
高温超导薄膜
RHEED 相似文献
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用衍射仪和Guinier聚焦照相机收集了铌酸锶钡钠系统一系列化合物的X射线粉末衍射图谱(CuKα辐射)。给出了Ba2NaNb5O15,SrBaNaNb5O15和Sr2.05Na0.90Nb5O15详细指标化了的粉末衍射数据,可代替原有的JCPDSX射线粉末衍射标准数据卡(卡片号为23-654,27-1408,27-1409和27-787)的数据。
关键词: 相似文献
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K. Buse 《Applied physics. B, Lasers and optics》1997,64(4):391-407
3 , LiTaO3, BaTiO3, Ba1-xSrxTiO3 (, BST), Ba1-xCaxTiO3 (, BCT), KNbO3, KTa1-xNbxO3 (, KTN), Sr1-xBaxNb2O6 (, SBN) and Bi12(Si,Ti,Ge)O20 (BSO, BTO, BGO) are discussed. Utilizing the knowledge on the charge transport processes, consequences for applications are
deduced; improved techniques for nondestructive readout of holograms with light of the recording wavelength are described.
Received: 14. October 1996 相似文献
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采用溶胶-凝胶法在氧化镁单晶衬底上制备了符合化学计量比的完全填充型铁电钾钠铌酸锶钡(KNSBN)薄膜,通过X射线衍射,摇摆曲线,X射线Φ扫描,扫描电子显微镜等方法研究了薄膜的微结构,采用Adachi法研究了薄膜的电光特性. 实验发现,KNSBN薄膜在氧化镁(001)单晶衬底上沿c轴外延生长,K+,Na+的引入有效地提高了薄膜的横向电光系数r51. 成分为K0.2Na0.2Sr0.24Ba0.56Nb2O6, K0.2Na0.2Sr0.6Ba0.2Nb2O6, K0.2Na0.2Sr0.72Ba0.08Nb2O6的三种KNSBN薄膜的r51值分别为108.52pm/V, 119.98pm/V, 126.96pm/V,r51的数值随Sr2+含量增加而增大.
关键词:
横向电光系数
钾钠铌酸锶钡
外延生长 相似文献
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Photorefractive waveguides in oxide crystals: fabrication, properties, and applications 总被引:2,自引:0,他引:2
D. Kip 《Applied physics. B, Lasers and optics》1998,67(2):131-150
3 , LiTaO3, BaTiO3, KNbO3, SrxBa1-xNb2O6 (0.25≤x≤0.75, SBN), and Bi12(Si,Ti,Ge)O20 (BSO, BTO, BGO) waveguides are discussed. Furthermore, the suitability of photorefractive waveguides for nonlinear optical
components is demonstrated in some examples.
Received: 21 April 1998/Revised version: 28 May 1998 相似文献
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Epitaxial Sr0.6Ba0.4Nb2O6(SBN60)/La0.7Sr0.3CoO3 heterostructures were fabricated on LAO(0 0 1) substrates using pulsed laser deposition (PLD). Their structural properties were investigated by X-ray diffraction. The θ-2θ scans showed single crystalline Sr1−xBaxNb2O6 (SBN) and LaxSr1−xCoO3 (LSCO) layers with a 〈0 0 1〉 orientations perpendicular to the substrate plane. Phi scans on the (2 2 1) plane of SBN layer indicated that the films have two in-plane orientations with respect to the substrate. The SBN unit cells were rotated in the plane of the film by ±18.4° as well as ±45° with respect to the LAO substrate. This rotation was explained by considering the lattice matching between films and substrate, and minimization of electrostatic energy. Spectroellipsometry (SE) was used to characterize the depth profile, the microstructural inhomogeneities, including voids and surface roughness, refractive indices and extinction coefficients of the films. 相似文献
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The diffuse transition of a rare earth ion doped SBN (BaxSr1?xNb2O6) was studied by measuring the spontaneous polarization Ps, and the dielectric constant ?. The phase transition of SBN can be regarded as a special case of a second order transition. 相似文献
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N. D. Scarisoreanu G. Dinescu R. Birjega M. Dinescu D. Pantelica G. Velisa N. Scintee A. C. Galca 《Applied Physics A: Materials Science & Processing》2008,93(3):795-800
SBN thin films were grown on MgO and Silicon substrates by PLD and RF-PLD (radiofrequency assisted PLD) starting from single
crystal Sr0.6Ba0.4Nb2O6 and ceramic Sr0.5Ba0.5Nb2O6 stoichiometric targets. Morphological and structural analyses were performed on the SBN layers by AFM and XRD and optical
properties were measured by spectroellipsometry. The films composition was determined by Rutherford Backscattering Spectrometry.
The best set of experimental conditions for obtaining crystalline, c-axis preferential texture and with dominant 31° in-plane orientation relative to the MgO (100) axis is identified. 相似文献
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Magnetic interaction in Mg, Ti, Nb doped manganites 总被引:4,自引:0,他引:4
I.O. Troyanchuk M.V. Bushinsky H. Szymczak K. Bärner A. Maignan 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(1):75-80
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
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Single crystals of barium strontium niobate Sr0.61Ba0.39Nb2O6 (SBN) subjected to high-temperature annealing are shown to be more uniformly polarized in a dc electric field than unannealed samples. The experiments are carried out with undoped SBN crystals and with chromium-and cerium-doped SBN crystals. 相似文献
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固相法合成系列名义组成为Bi2-xNbxSr2Ca2Cu3Oy(x=0—1.0)的样品,电学和磁学测量表明,当掺入x=0.2—0.3的Nb有明显加强2223相生成的作用,配比为Bi1.7Nb0.3Sr2Ca2Cu3Oy时最佳;当掺Ba以部分取代Sr后有明显协同Nb促进2223相生成的作用,比单掺Nb效果更为显著,其中以Bi1.7Nb0.3Sr1.8Ba0.2Ca2Cu3Oy为最优组成。热重分析(TGA)实验显示,掺Nb(Ba)后样品在~600°C出现吸氧增重;XPS中的O1s峰显示掺Nb(Ba)后除~531eV的主峰外,在~529eV的肩峰更加明显;讨论了Nb(Ba)对晶体结构的可能影响。
关键词: 相似文献