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采用脉冲电子束沉积技术, 在SrTiO3衬底上成功制备了高质量的Nd1.85Ce0.15CuO4(NCCO)薄膜. 通过改变薄膜的沉积温度、厚度、退火条件以及沉积频率, 获得了具有不同生长条件的NCCO薄膜样品. 对样品R-T曲线进行分析, 得到了上述因素对薄膜超导电性的影响规律, 并进一步说明了这些因素对薄膜的超导电性造成影响的原因. 通过与脉冲激光沉积技术类比, 定量分析了沉积过程中靶与基片距离同沉积气压之间的关系. 相似文献
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采用脉冲电子束沉积技术在(100)取向单晶钛酸锶衬底上沉积出具有高取向的La0.67Ca0.33MnO3薄膜, 并用电子束曝光技术获得不同宽度的微桥结构, 对这些微桥结构的输运性能进行了研究. 当微桥的宽度为2和1.5 μm时, 与大面积薄膜相比, 其金属绝缘体转变温度TP变化不大. 当微桥的宽度为1 μm时, TP降低约50 K. 当微桥宽度减小到500 nm以下, 没有观察到金属-绝缘体转变. 对不同宽度微桥的磁电阻曲线进行分析发现, 随着微桥宽度减小, 低场磁电阻也变 小, 高场磁电阻变化不大. 相似文献
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e-H碰撞微分散射截面的场论计算方法研究 总被引:1,自引:0,他引:1
本采用量子场论的方法,构想了一种简化的电子与氢原子碰撞的模型,结合光学势模型中的可加性规则的思想,计算了电子被氢原子散射的微分散射截面,并与单纯用光学势方法计算的结果进行了比较.创新性的将场论方法应用于电子与原子的碰撞截面计算. 相似文献
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Film Thickness Dependence of Rectifying Properties of La1.85Sr0.15CuO4/Nb-SrTiO3 Junctions
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In this work, p-n junctions are made from directly depositing optimal doped La1.85Sr0.15CuO4 (LSCO) films on n-type Nb-doped SrTiO3 substrates. Film thickness controlled rectifying behaviors are strikingly displayed. The starting points of the diffusion voltage reduction Vd-on change clearly with varying film thickness. Vd-on and Tc coincide with each other when the film thickness is larger than 300 nm, indicating a close relation between the two parameters. However, when the film is very thin (〈 350 nm) a departure between the two parameters was also observed. A possible reason for this is discussed within the framework of an inhomogeneous Sehottky contact. Enhanced interface inhomogeneity due to the tensile strain appears to be the origin. 相似文献
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Enhancing low-field magnetoresistance of La0.67Ca0.33MnO3 films deposited on anodized aluminium-oxide membranes
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In this paper we report a new method to fabricate nanostructured films, La0.67Ca0.33MnO3 (LCMO) nanostructured films have been fabricated by using pulsed electron beam deposition (PED) on anodized aluminium oxide (AAO) membranes, The magnetic and electronic transport properties are investigated by using the Quantum Design physics properties measurement system (PPMS) and magnetic properties measurement system (MPMS). The resistance peak temperature (Tp) is about 85 K and the Curie temperature (To) is about 250 K for the LCMO film on an AAO membrane with a pore diameter of 20nm. Large magnetoresistance ratio (MR) is observed near Tp. The MR is as high as 85% under 1 T magnetic field. The great enhancement of MR at low magnetic fields could be attributed to the lattice distortion and the grain boundary that are induced by the nanopores on the AAO membrane. 相似文献
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Ordered YBa2Cu3Oy nanowires have been fabricated by filling YBa2Cu3Oy melting liquid into the pores of the anodized alumina templates. X-ray powder diffraction proves that YBa2Cu3Oy nanowires crystallized in the Y-123 structure. The temperature dependence of ac susceptibility indicates a superconducting transition at 91 K for the YBa2Cu3Oy nanowire array. 相似文献