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推导出了任意振幅下的摆动周期相对误差的解析表达式,利用从头算起的数值方法,计算了振幅介于0°到90°之间的任意振幅摆动周期的相对误差. 相似文献
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采用固相反应法制备了Tb0.8Eu0.2MnO3多晶材料.对样品的X射线衍射(XRD)分析表明Eu3+固溶于TbMnO3中.测量了样品在低温(100 K ≤T≤ 300 K)和低频下(200 Hz≤f≤100 kHz)的复介电性质.在此温度区间内发现了两个介电弛豫峰.经分析认为低温峰(T≈170 K)起源于局域载流子漂移引起的偶极子极化效应,而高温峰(T≈290 K)则是由离子电导产生的边界和界面层的电容效应引起的.电阻率的测量显示在低温下(T≈230 K)存在明显的导电机制转变. 相似文献
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Reduced-temperature ordering of FePt nanoparticle assembled films by Fe30Pt70/Fe3O4 core/shell structure 下载免费PDF全文
In this paper, Fe30Pt70/Fe3O4 core/shell nanoparticles were synthesized by chemical routine and the layered polyethylenimine (PEI)-Fe30Pt70/Fe3O4 structure was constructed by molecule-mediated self-assembly technique. The dimension of core/shell structured nanoparticles was that of 4nm core and 2 nm shell. After annealing under a flow of forming gas (50%Ar2+30%H2) for 1 h at or above 400℃, the iron oxide shell was reduced to Fe and diffused to Pt-rieh core, which leaded to the formation of L1. phase FePt at low temperature. The x-ray diffraction results and magnetic properties measurement showed that the chemical ordering temperature of Fe30Pt70/Fe3O4 core/shell nanoparticles assembly can be reduced to as low as 400℃. The sample annealed at 400℃ showed the eoereivity of 4KOe with the applied field of 1.5T. The core/shell structure was suggested to be an effective way to reduce the ordering temperature obviously.[第一段] 相似文献
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The domain structures of Pt1-xCux/Co multilayer films in as-grown and remanent states have been investigated by using magnetic force microscope. The magnetic domain patterns are strongly influenced by the Cu concentration. For pure Pt/Co multilayer in as-grown state, its domain pattern is depicted as island-like one; however, with the Cu doped in Pt spacer layers, the doman patterns become dot-like, but the island-like domain pattern appears again for the Cu concentration of 14 at%. The domain patterns variation can be attributed to the change of effective perpendicular anisotropy Kueff due to the effect of Cu atom doped in the Pt spacer layers. Besides, the domain structures of Pt/Co multilayer films in remanent state after the application of various perpendicular magnetic fields have also been studied. 相似文献
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根据具有巨磁阻抗(GMI)效应的实际三明治样品的状况,提出三明治结构作为理论计算的模型,考虑了磁性层的各向异性场,利用一定边界条件下的Maxwell方程和Landau-Lifshitz方程对模型进行了理论计算,得到了阻抗与频率、各向异性场等因素间的函数关系.在此基础上,着重讨论了各向异性场Hk的作用.Hk的大小、方向均会对GMI效应造成影响,最佳的Hk应在400A/m左右,位于面内并与电流垂直.还证实了三明治结构中磁性层的磁致伸缩只会减弱G
关键词:
巨磁阻抗(GMI)效应
三明治膜
Maxwell方程
Landau-Lifshitz方程 相似文献
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传统的半导体三极管(又称晶体三极管或晶体管)由两个PN结和三个电极构成,从结构上看有NPN和PNP两种基本类型.其工作原理是大家所熟知的.晶体管的成功研制极大的带动了半导体工业的发展.晶体管的应用已渗入到国民经济的各个领域. 相似文献
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根据两种具有巨磁阻抗(GMI)效应的磁性材料实验样品,提出了两种理论模型(同轴电缆结构——Cu丝外覆软磁材料的圆柱形;三明治结构——Cu或Ag为中间层外包软磁层的三明治膜),利用Maxwell方程和Landau_Lifshitz方程对其GMI效应的机理进行了理论研究.证明了两种模型的差别仅仅是形状因子的不同,从而由理论上证实了两种结构GMI效应增强的内在一致性.证实了在同种磁性材料情况下,双层结构具有结构方面的优越性.并对照实验数据讨论了参数的影响,得到与实验定性相符的结果.
关键词:
巨磁阻抗效应
三明治膜
Maxwell方程
Landau_Lifshit 相似文献
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