Li'an HAN
材料科学技术（英文）
Lattice effect on magnetic and electrical transport properties of Ln2/3Pb1/3MnO3 (Ln=La, Pr, Nd) films prepared by RF magnetron sputtering technique were investigated. With the decrease of the average ions radius , the structure of Ln2/3Pb1/3MnO3 (Ln=La, Pr, Nd) targets transit from the rhombohedral phase to the orthorhombic phase, and the Curie temperature reduces rapidly with the decrease of . The electrical properties show that films are the metallic state which can be fitted to the formula: ρ(T)= ρ0+ρ1T2+ρ2T4.5 at low temperatures. The temperature range of the ferromagnetic metallic state becomes narrow with the decrease of . The phenomenon can be explained by the lattice effect.
关键词:
Lattice effect
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films
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Lattice
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effect
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Magn
H E Misak
,
S Mall
新型炭材料
doi:10.1016/S1872-5805(15)60186-X
碳纳米管( CNTs)在电力转换领域具有潜在前景。本文表征碳纳米管纱随时间变化对电力的转换性能影响。通过建立I-V关系，结果表明存在3个区域，即线性、非线性和下降区域。线性区域表明呈现低且恒定电阻。当恒定电压处于I-V线性区域时，输出电流强度不随时间而改变。然而，当恒定电压处于非线性区域时，电流强度以指数级下降后随时间而趋平。在恒电流测试下，电压仅在电流强度处于非线性区时增加。依赖时间的导电性能可通过短路来理解。短路发生在非线性区域的碳纳米管纱中炽热部位，会导致热性能降低。通过热图像、热重分析、扫描电镜和能谱分析等手段对碳纳米管纱进行分析。
关键词:
碳纳米管
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纱
,
电性能
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时间依赖
,
铁球
Changpeng LI
,
Jinfeng WANG
,
Wenbin SU
,
Hongcun CHEN
,
Wenxin WANG
材料科学技术（英文）
The electrical properties of (Nb, Li)-doped SnO2 ceramics as a new varistor material were investigated. The sample 97.95%SnO2.0.50%Li2O.0.05%Nb2O5 (mol fraction) sintered at 1450ºC possess the highest density (r=6.77 g/cm3) and nonlinear electrical coefficient (a=11.6). The substitution of Sn4+with Li+ increases the concentration of oxygen vacancies, together with the formation of solid solution, which will increase the sintering rate greatly and decrease the optimized sintering temperature. The substitution of Sn4+with Li+ and the variation of temperature play very important effects on the densities, dielectric constant, nonlinear electrical properties and other characteristics of the samples. The properties of the grain boundary barrier and the microstructural characteristics were investigated to ensure the effect of the dopants and the temperature. A grain boundary defect barrier model was used to illustrate the grain boundary barriers formation in SnO2-Li2O-Nb2O5 varistors.
关键词:
Varistors
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null
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null
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null
