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利用固相反应方法制备了名义成分为La2 / 3Ca1 / 3Mn1 -xFexO3(0 .0 1≤x≤ 0 .2 0 )的一系列样品 .在整个掺杂范围内晶体结构没有明显变化 .在室温下测量了各样品的M ssbauer谱 ,拟合结果表明 +3价高自旋态的铁离子占据锰的八面体晶位 ,随Fe掺杂量的增加 ,铁离子的 3d电子出现局域化趋势 ,并伴随Fe O配位体畸变程度的增强 .本文对此进行了讨论 .  相似文献   
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Conductive perovskite BaPb03 (BPO) films as a potential electrode material of PZT capacitors used in ferroelectric random access memory are prepared by rf magnetron sputtering. An x-ray diffractometer and standard four probe method are employed to investigate the dependence of growth conditions on crystal structure and conductivity of BPO films. It is found that BPO films with perovskite phase can be obtained at substrate temperatures above 425℃, and the sample with the lowest resistivity is obtained at 450℃ under pure argon atmosphere. Using this BPO film as electrode, ferroelectric properties of BPO/PZT/BPO and Pt/PZT/BPO sandwiched structures are evaluated. Their remanent polarization and coercive field are 36.6 ℃/cm^2 (81.3 k V/cm) and 36.9℃/cm^2 (89.1 kV/cm), respectively. The coercive field of the former structure is lower than that of the latter, but remanent polarizations are almost the same. In addition, the results imply that BPO electrode is helpful to improve the fatigue resistance of PZT. The reasons are discussed.  相似文献   
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对La0.7Ca0.3MnO3材料样品在77K至室温范围的一系列温度, 测量了正电子寿命谱和多普勒展宽谱.结果表明在居里温度附近正电子平均寿命和多普勒线形参数S出现明显变化, 反映了此类化合物晶格结构的不稳定性.本文对此进行了讨论.  相似文献   
4.
Ba0.8Sr0.2 TiO3/CoFe2O4 (BST/CFO) magnetoelectric composite thin films of 2-2-type structures are prepared onto Pt/Ti/SiO2/Si substrates by a sol-gel process and spin coating technique. The structure of the prepared thin film is substrate/BST/CFO/. . ./CFO/BST. Three CFO ferromagnetic layers are separated from each other by a thin BST layer. The upper CFO layer is magnetostatically coupled with the lower CFO layer. Subsequent scanning electron microscopy investigations show that the prepared thin films exhibit good morphologies and have a compact structure, and the cross-sectional mierographs clearly display a multilayered nanostructure of multilayered thin films. The composite thin films exhibit good magnetic and ferroelectric properties. The spacing between ferromagnetic layers can be varied by adjusting the thickness of intermediate BST layer. It is found that the strength of magnetostatic coupling has a great impact on magnetoelectric properties of composite thin film; that is, the magnetoelectric voltage coefficient of the composite thin film tends to increase with the decrease of pacing between two neighboring CFO ferromagnetic layers as a result of magnetostatic coupling effect.  相似文献   
5.
闻心怡  王耘波  周文利  高俊雄  于军 《物理学报》2011,60(9):97701-097701
采用射频磁控溅射法在Pt/TiOx/SiO2/Si基片上制备了以BaPbO3(BPO)为缓冲层的Pb(Zr0.52,Ti0.48)Nb0.04O3 (Nb掺杂PZT, PZTN)薄膜.通过调整BPO层厚度,为该PZTN薄膜引入了不同的张应力.当BPO层厚度分别为68 nm和135 nm时,PZTN薄膜呈现随机取向,采用2θ-s 关键词: PZT 准同形相界 掠射扫描方式 结构精修  相似文献   
6.
利用固相反应方法制备了名义成分为La2/3Ca1/3Mn1-xFexO3(0.01≤x≤0.20)的一系列样品。在整个掺杂范围内晶体结构没有明显变化。在室温下测量了各样品的Mossbauer谱,拟合结果表明+3价高自旋态的铁离子占据锰的八面体晶体,随Fe掺杂量的增加,铁离子的3d电子出现局域化趋势,并伴随Fe-O配位体畸变程度的增强,本文对此进行了讨论。  相似文献   
7.
Au/PZT/BIT/p-Si异质结的制备与性能研究   总被引:2,自引:2,他引:0       下载免费PDF全文
采用脉冲激光沉积(PLD)工艺,制备了以Bi4Ti3O12(BIT)为过渡阻挡层的Au/PZT/BIT/p-Si异质结.研究了BIT铁电层对Pb(Zr0.52Ti0.48)O3(PZT)薄膜晶相结构、铁电及介电性能的影响,对Au/PZT/BIT/p-Si异质结的导电机制进行了讨论.氧气氛530℃淀积的PZT为多晶铁电薄膜,与直接淀积在Si基片上相比,加入BIT铁电层后PZT铁 关键词: 铁电薄膜 异质结构 脉冲激光沉积(PLD)  相似文献   
8.
In this paper, we rigorously derive the governing equations describing the motion of a stable stratified fluid, from the mathematical point of view. In particular, we prove that the scaled Boussinesq equations strongly converge to the viscous primitive equations with density stratification as the aspect ratio goes to zero, and the rate of convergence is of the same order as the aspect ratio. Moreover, in order to obtain this convergence result, we also establish the global well-posedness of stro...  相似文献   
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