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Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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Science china(physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2, CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 Key laboratory of Beam Technology & Materials Modification of the Ministry of Education, institute of Low Energy Nuclear physics, beijing Normal University, beijing 100875, china 2 beijing Radiation Center, beijing 100875, china 3.laboratory of optical physics, institute of physics, chinese academy of Sciences, beijing 100080, china 4 Key laboratory of Advanced Materials of the Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, beijing 100084, china 5 beijing National Center for Electron Microscopy, Tsinghua University, beijing 100084, china 1. Key laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. laboratory of optical physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 4. Key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing 100084 China 5. beijing National Center for Electron Microscopy Tsinghua University Beijing 100084 China

The LaMn1-xTexO3+δ (x=0.1, 0.2, 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2+ and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2+, Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2+ and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2+ and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport

Approaches to improving critical current density of YBCO superconducting thick films deposited by electrophoresis

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Science china(physics,Mechanics & Astronomy) 2004年第2期47卷 165-172页

作者： ZHU Yabin1,2, ZHOU Yueliang2, LIU Zhen2, WANG Shufang2, CHEN Zhenghao2, L?Huibin2, YANG Guozhen2, XIAO Ling3, REN Hongtao3, JIAO Yulei3 & ZHENG Minghui3 1. Department of physics, College of Science, beijing Jiaotong University, beijing 100044, china 2. laboratory of optical physics, institute of physics and Center for Condensed Matter physics, chinese academy of Sciences, beijing 100080, china 3. General Research institute for Nonferrous Metals, beijing 100088, china Correspondence should be addressed to Zhu Yabin (email: ybzhu@***) 1. Department of physics College of Science Beijing Jiaotong University 100044 Beijing China 2. laboratory of optical physics institute of physics and Center for Condensed Matter physics Chinese Academy of Sciences 100080 Beijing China 3. General Research institute for Nonferrous Metals 100088 Beijing China

Fabrication of YBCO superconducting thick films by electrophoresis has been widely reported. However, the value of critical current density (J c) is far from what the practical application requires. The superconducting thick films are obtained using top-seeded melt growth method with different proportional Y2BaCuO5 (Y211) addition. High-pressure oxygen has been used in the annealing process to improve the uniformity of the oxygen content in the superconducting thick films. When 40mol% Y211 powder is added to the YBa2Cu3O7–5 (Y123) powder,J c for the superconducting thick film by approaches described above reaches 7.008×103 A/cm2 (77 K, 0 T), which is greater than the value ever reported.

关键词： YBCO thick films, electrophoretic deposition, melt-textured.

Colossal magnetoresistive p-n junctions of perovskite oxide La_(0.9)Sr_(0.1)MnO_3/SrNb_(0.01)Ti_(0.99)O_3

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chinese Science Bulletin 2003年第13期48卷 1328-1330页

作者： L Huibin, DAI Souyu, CHEN Zhenghao, YAN Lei, ZHOU Yueliang & YANG Guozhen laboratory of optical physics, institute of physics & Center for Condensed Matter physics, chinese academy of Sciences, 100080 beijing, china laboratory of optical physics Center for Condensed Matter Physics Chinese Academy of Sciences 100080 Beijing China

We have successfully fabricated the colossal magnetoresistive (CMR) p-n junctions of perovskite oxide La0.9Sr0.1MnO3/SrNb0.01Ti0.99O3 (LSMO/SNTO) with laser molecular beam epitaxy. The I-V characteristics of the LSMO/SNTO p-n junctions as a function of applied magnetic field (05 T) were studied between 100 and 300 K. We found that the p-n junction exhibited the CMR behavior. The CMR ratio rR/R0 (rR = RH - R0) is positive in magnetic fields below 0.13 T and at high temperature, while it displays a negative CMR near 100 K and in magnetic fields over 0.13 T. The CMR ratio values are 8% at 0.1 T and 13% at 5 T and 300 K, 40% at 0.1 T and 150 K, 10% at 0.13 T and 60% at 5 T and 100 K. The CMR behavior of the p-n junction is different from those of the LaMnO3 compound family.

关键词：巨磁电阻钙钛矿氧化物 LSMO/SNTO CMR 激光分子束外延超导体

POLYMETHYLMETHACRYLATE FILMS IN THE STATE OF HIGH GLOBAL CHAIN ORIENTATION BUT NEARLY RANDOM SEGMENTAL ORIENTATION

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chinese Journal of Polymer Science 1999年第3期17卷 215-220页

作者： Rui Song Jing Chen Jin-gui Gao Xin Lin Qing-rong Fan Polymer physics laboratory, institute of Chemistry, chinese academy of Sciences, beijing 100080, china chinese Acad Sci Inst Chem Polymer Phys Lab Beijing 100080 Peoples R China

PMMA films in the high global chain orientation and nearly random segmental orientation (GOLR) state were prepared by uni-axially drawing at temperatures 20 similar to 30 degrees C above its glass transition temperature, T-g, and their isotropic and anisotropic properties were studied. Experimental results show that this kind of amorphous state, the GOLR state, is nearly isotropic in optical birefringence, IR-dichroism and X-ray diffraction patterns, but is very anisotropic in behaviors of thermal expansion, solvent-swelling and stress-strain.

关键词： orientation uniaxial stretching polymethylmethacrylate optical birefringence WAXD infrared spectroscopy

Narrow line Seyfert 1 galaxies: where are the broad line regions?

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Science china(physics,Mechanics & Astronomy) 2010年第12期53卷 2307-2311,2339-2343页

作者： MAO WeiMing 1,2,3 , HU Chen 2 , WANG JianMin 2 , BIAN WeiHao 4 , ZHANG Shu 2 & ZHAO Gang 1 1 Key laboratory of optical Astronomy, National Astronomical Observatories, chinese academy of Sciences, beijing 100012, china 2 Key laboratory for Particle Astrophysics, institute of High Energy physics, chinese academy of Sciences, beijing 100049, china 3 Graduate University of the chinese academy of Sciences, beijing 100049, china 4 Department of physics, Nanjing Normal University, Nanjing 210011, china 1. Key laboratory of optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China3. Graduate University of the Chinese Academy of Sciences Beijing 100049 China4. Department of Physics Nanjing Normal University Nanjing 210011 China

A sample consisting of 211 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the Hβ profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined Hβ reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

关键词： black hole physics galaxies: evolution quasars: general

An improved δ-Eddington approximation

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chinese Science Bulletin 1999年第4期44卷 304-309页

作者： QIU Jinhuaninstitute of Atmospheric physics , chinese academy of Sciences , beijing 100029, china institute of Atmospheric physics Chinese Academy of Sciences Beijing China

Based on an accuracy analysis of two-stream approximations, an improved δ-Eddington ap-proximation is developed. The approximation has much better accuracy than all exiting two-stream ap-proximations as the optical depth is less than unity. As the surface reflectance is zero and the opticaldepth is less than unity, errors in both transmission and reflection calculated by the present approxima-tion are more one time less than those by other two-stream approximations. In the case of aerosol opti-cal depth of3.5% and 2.6%, respectively. The errors are over 41% and one times lessthan those by Eddington or δ-Eddington.

关键词： radiation flux fractional factor of δ-function Eddington approximation.

Colossal magnetoresistance and spin-glass properties of La(1-x)TexMnO3(x=0.04,0.1)

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chinese Science Bulletin 2003年第13期48卷 1321-1324页

作者： TAN Guotai, DUAN Peng, DAI Shouyu, CHEN Zhenghao, LU Huibin & ZHOU Yueliang laboratory of optical physics, institute of physics & Center for Condensed Matter physics, chinese academy of Sciences, beijing 100080, china Correspondence should be addressed to Chen Zhenghao (e-mail: zhchen @***) laboratory of optical physics Institute of Physics & Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 China

For the first time, a novel material of La1-x- TexMnO3 (x = 0.04, 0.1), in which the La ions are replaced by the nonmetal element Te in the Chalcogen, has been synthesized. The material has a rhombohedral lattice with the space group of R3c, and Te ions have a tetravalence state. The curves of the resistivity vs. temperature indicate that this material has the property of a metal-semiconductor transition and the colossal magnetoresistance (CMR) effect. The maximum magnetoreistance ratio MR=[(0)()]/(0)H? is about 51% at 4 T for x = 0.1. Besides, a spin-glass behavior at low magnetic fields is observed in this compound.

关键词：巨磁电阻 La1-xTexMnO3 镧碲物理性质

某些类氖离子和类镍离子等离子体状态对应关系的研究

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物理学报 2003年第9期52卷 2200-2205页

作者：燕飞张杰鲁欣中国科学院物理研究所光物理重点实验室北京100080

利用一维拉格朗日流体动力学程序Med10 3详细研究了产生类镍Ag ,Cd ,In ,Sn,Sb离子和类氖Fe ,Co ,Ni,Cu,Zn离子的等离子体状态 .通过对电子温度、离子丰度、离子数密度等状态参量的分析比较 ,得到了这两类等离子体状态之间的对应关系 .... 详细信息

利用一维拉格朗日流体动力学程序Med10 3详细研究了产生类镍Ag ,Cd ,In ,Sn,Sb离子和类氖Fe ,Co ,Ni,Cu,Zn离子的等离子体状态 .通过对电子温度、离子丰度、离子数密度等状态参量的分析比较 ,得到了这两类等离子体状态之间的对应关系 .即类镍银的等离子体状态与类氖铁的相近 ,类镍镉的与类氖钴的相近 ,依次类推 .

关键词：类氖离子类镍离子等离子体状态对应关系 X射线激光一维拉格朗日流体动力学程序等离子体诊断

CeO_2 thin films grown on biaxially textured nickel(001)

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chinese Science Bulletin 1998年第20期43卷 1718-1722页

作者： WANG Rongping, XIONG Xuming, Guo Xiangxin, ZHOU Yueliang, L Huibin, PAN Shaohua, CHEN Zhenghao and YANG Guozhen laboratory of optical physics, institute of physics and Center for Condensed Matter physics, chinese academy of Sciences, beijing 100080, Ch laboratory of optical physics Institute of Physics and Center for Condensed Matter Physics Chinese Academy of Sciences Beijing China

CeO\-2 films have been grown on biaxially textured Ni substrates at various temperatures. The results show that CeO\-2 films without IBAD are dominated by (111) orientation from room temperature to 800℃ while the preferential orientation of CeO\-2 films with IBAD is (001) at lower deposition temperature and (111) at deposition temperature higher than 450℃. CeO\-2 films with better in_plane texture and out_of_plane orientation can be grown at 360℃ with 240 eV ion energy and 200 μA/cm\+2 ion current density.

关键词： CeO\-2 films biaxial nickel.