【摘 要】
：
The microstructure, magnetic and transport properties of the heterogeneous system with a nominal composition (1/m)Ag2O-La0.833K0.167MnO3 (1/m is molar ratio wit
【机 构】
：
National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanji
论文部分内容阅读
The microstructure, magnetic and transport properties of the heterogeneous system with a nominal composition (1/m)Ag2O-La0.833K0.167MnO3 (1/m is molar ratio with m = 32, 16, 8, 4, and 2) have been studied.The x-ray diffraction pattes show that all the samples are two-phase composite and consist of a magnetic La0.833K0.167MnO3 (LKMO) perovskite phase and a nonmagnetic metal Ag phase. The room-temperature magnetoresistance (MR) effect is enhanced significantly due to the addition of Ag. For the m = 4 sample, we obtain MR values up to 32% under a lower field of 0.5 T and 64% under a higher field of 5.5 T at the temperature of 300K, which are much larger than the corresponding MR values (10% and 35%) of the LKMO sample without Ag. In the low-temperature range from 4.2K to 250K, the MR values of the Ag-added samples however decrease with the increasing Ag content in the samples. This effect is discussed qualitatively by using the relative contribution from the intrinsic MR effect and the extrinsic MR effect including the spin-polarized-tunnelling and spin-dependent scattering effects in different temperature regions.
其他文献
We study the strangeness of a chemically equilibrating quark-gluon plasma at finite baryon density based on the and will accelerate with the change of the initi
随着九年制义务教育教材改革的推进，“通过义务教育阶段的数学学习，使学生能够具备学习能力及探究能力”已成为数学教学的一个重点。在实际教学中注重对学生能力的培养，引起了广大教师的高度重视，如何培养和发展学生能力，如何培养学生的解题技巧在数学教学中愈来愈显得重要。本文就数学教学方法的几种变换技巧论述如下： 一、巧用“平移”“等积”变换找出突破口，化繁为简 “平移”是数学学习中常用的一种分析方
A numerical study of the defect modes in two-dimensional photonic crystals with deformed triangular lattice is presented by using the supercell method and the f
周期函数的判定是高中数学中常遇到的问题，又是历年高考的重点，近年来，在高考中更是常常利用抽象函数对其进行考察，但很多学生对其知之甚少或理解不透，考生得分率较低。为了使学生能更好地掌握周期函数，掌握求函数的周期及运用函数的周期性解决一些简单的数学问题。本文就函数周期性的判定作些探讨，仅供参考。 一、周期函数的性质 （1）若T（T≠0）是f（x） 的周期，则-T也是f（x）的周期。 （2
江西省2008年秋季开始启用新课标新教材教学，笔者有幸参加了省级骨干教师的新课标培训，对新教材的教学目标和指导思想以及对教材的安排和实施也有了一定的了解。现就高中英语听力教材的运用方面谈谈看法和做法。 一、充分利用课内听力教材 新教材在听力任务的设置、听力材料的选取上，既贴近学生的生活又符合学生的学情，并紧扣各单元主题。因此，教师只要运用恰当，就能有效提高学生的听力能力。 1.听前热
When two optical pulses copropagate inside a single-modefibre, intensity-dependent refractive index couples the pulses through a cross-phase modulation (XPM). W
The point-to-point Feynman quantum propagator has an analytic form only for quadratic potentials. We apply the split operator approach to obtain a propagator m
High-pressure phases of BC3 are studied within the local density approximation under the density functional theory framework.
The third-order optical nonlinearities and responses of a squarylium dye, 2,4-di-3-guaiazulenyl-1,3-dihydroxycyclobutenediylium dihydroxide, in tetrahydrofuran
Electroluminescent characteristics of n-ZnO/p-GaN hetero junctions under forward and reverse biases are studied.Emissions at 389nm and 570nm are observed under