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Science china(physics,Mechanics & Astronomy) 2007年第2期50卷 240-248页

作者： WANG WeiXian1,ZHOU Fang2,TAN Shun1,WU Huan1 & ZHANG YuHeng1 1 national High Magnetic Field laboratory,University of Science and Technology of china,Hefei 230026,china 2 national laboratory for superconductivity,lnstitute of physics and the center for condensed matter physics,chinese academy of sciences,beijing 100080,china 1. national High Magnetic Field laboratory University of Science and Technology of China Hefei 230026 China 2. national laboratory for superconductivity Institute of Physics and the Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 China

In the strict sense, it is not very clear why with magnetic field increasing, the normal-superconductive (NS) transition becomes broad for Bi2Sr2CaCu208+δ(Bi2212) while the NS transitions are almost parallel for La193Sroo7Cu04+δ(La214). In this paper, R-T relations are measured by the six-probe method. We propose a moving mechanism of the pancake vortex and vortex line for Bi2212. The theoretical curves fit the experiment data well.

关键词： superconductivity superconductive pancake vortex dynamics

An Explicit Function Expression for dc Bias and Temperature Dependence of Magnetoresistances in Magnetic Tunnel Junctions

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Journal of Materials Science & Technology 2002年第6期18卷 497-501页

作者： Xiufeng HANState Key laboratory of Magnetism, Institute of physics and center of condensed matter physics, chinese academy of sciences, beijing 100080, china chinese Acad Sci Inst Phys State Key Lab Magnetism Beijing 100080 Peoples R China chinese Acad Sci Ctr Condensed Matter Phys Beijing 100080 Peoples R China

An explicit function expression for the bias voltage or/and temperature dependences of tunnel magnetoresistance ratio and resistances were obtained with a unique set of intrinsic parameters. Two of these intrinsic parameters are the Curie temperature TC and the density of state (DOS) for itinerant majority and minority electrons ξ(ρM/ρm), which are the eigen parameters of ferromagnetic electrodes. Others are the spin-dependent matrix-element ratio (i.e., |Td|2/|TJ|2 ) and the anisotropic-wavelength-cutoff energy ECγ of spin-wave spectrum in magnetic tunnel junction (MTJ), which are the structure parameters of an MTJ. These intrinsic parameters can be predetermined using the experimental measurement or, in principle, using the first-principle calculation method for an MTJ with the three key layers of FM/I/FM. Furthermore, a series of experimental data for an MTJ, for example, a spin-valve-type MTJ of Ta (5 nm)/Ni79Fe21(25 nm)/lr22Mn78(12 nm)/Co75Fe25(4 nm)/AI(0.8 nm)-oxide/Co75Fe25(4 nm)/Ni79Fe21(20 nm)/Ta (5 nm) in this work, can be self-consistently evaluated and explained using such concise explicit function formulations.

关键词： Magnetic tunnel junction TMR Spin-electron transport Magnon excitation Spin-polarization Magnetotransport

Anomalous Hall effect in perpendicular CoFeB thin films

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chinese physics B 2014年第4期23卷 9-17页

作者：朱涛 Institute of physics and beijing national laboratory for condensed matter physics Chinese Academy of Sciences

Our recent research achievements in the perpendicular magnetic anisotropy （PMA） properties of the CoFeB sand- wiched by MgO and tantalum layers are summarized. We found that the PMA behaviors of Ta/CoFeB/MgO and MgO/CoFeB/Ta thin films are different. The larger PMA in the latter film is related to the lower magnetization of CoFeB deposited on MgO. Furthermore, we have demonstrated a large anomalous Hall effect in perpendicular CoFeB thin fihn. Our results show large anomalous Hall resistivity, large longitudinal resistivity, and low switching field can be achieved, all at the same time, in the perpendicular CoFeB thin film. Anomalous Hall effect with high and linear sensitivity is also found in an MgO/CoFeBFFa thin film with a thick MgO layer, which opens a door tbr future device applications of perpendicular ferromagnetic thin films.

关键词： anomalous Hall effect perpendicular magnetic anisotropy magnetic properties of interfaces

Single-molecule studies of DNA by molecular combing

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Progress in Natural Science:Materials International 2007年第5期17卷 493-499页

作者： Liu Yuying, Wang Pengye and Dou Shuoxing (College of Science, china Agricultural University, beijing 100083, china laboratory of Soft matter physics, beijing national laboratory for condensed matter physics, Institute of physics, chinese academy of sciences, beijing 100080, china) [a]College of Science China Agricultural University Beijing China [b]laboratory of Soft matter physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of Physics Chinese Academy of Sciences Beijing China

Molecular combing is a powerful method for aligning a large array of DMA molecules onto a surface. It is a process whereby DNA molecules are stretched and aligned on a glass surface by the force via fluid flow. The ability to comb up to several hundred DNAs on a single cover slip allows for a statistically significant number of measurements to be made. These features make molecular combing an attractive tool for genomic studies, such as DNA replication, DNA transcription, DNA-protein interaction and so on. In this review article, we discuss the molecular combing principle, method and its applications.

关键词： DNA molecule molecular combing DNA-protein interaction.

superconductivity at 36 K in gadolinium-arsenide oxides GdO_(1-x)F_xFeAs

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Science china(physics,Mechanics & Astronomy) 2008年第6期51卷 719-722页

作者： CHENG Peng, FANG Lei, YANG Huan, ZHU XiYu, MU Gang, LUO HuiQian, WANG ZhaoSheng & WEN HaiHu national laboratory for superconductivity, Institute of physics, chinese academy of sciences, beijing 100190, china beijing national laboratory for condensed matter physics, Institute of physics, chinese academy of sciences, beijing 100190, china 1. national laboratory for superconductivity Institute of Physics Chinese Academy of Sciences Beijing 100190 China 2. beijing national laboratory for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

In this paper we report the fabrication and superconducting properties of GdO1-xFxFeAs. It was found that when x is equal to 0.17, GdO0.83F0.17FeAs is a su-perconductor with the onset transition temperature Tcon ≈ 36.6 K. Resistivity anomaly near 130 K was observed for all samples up to x = 0.17, and such a phenomenon is similar to that of LaO1-xFxFeAs. Hall coefficient indicates that GdO1-xFxFeAs is conducted by electron-like charge carriers.

关键词： iron-based superconductor high-temperature superconductor

A 3.9 V polyanion-type cathode material for Li-ion batteries

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Progress in Natural Science:Materials International 2011年第3期21卷 211-215页

作者： Lei LIU,Bin ZHANG,Xue-jie HUANG beijing national laboratory for condensed matter physics, Institute of physics,chinese academy of sciences,beijing,100190,china beijing national laboratory for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

Monoclinic phase LiFeSO4F was synthesized by a simple fast solid state reaction from the mixture of FeSO4·7H2O and LiF pulverized by high energy ball milling.m-LiFeSO4F was confirmed by GITT measurement to be a 3.9 V polyanion-type cathode materials for Li-ion *** electrochemical activity can be enhanced by addition of carbon.A discharge capacity of 105 mA·h/g (70%of theoretical value) was achieved for a m-LiFeSO4F/CNT *** separation behavior during lithium extraction and insertion was observed by ex-situ XRD test.

关键词： LiFeSO4F polyanion cathode Li-ion battery

Oxygen pressure dependent electro-resistance in La_(0.9)Sr_(0.1)MnO_3 thin films grown by laser molecular beam epitaxy

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 232-236页

作者： OUYANG SiHua1,2,WANG ChunChang2,LIU GuoZhen2,HE Meng2, JIN KuiJuan2,DANG ZhiMin1 & L HuiBin21 College of Materials Science and Engineering,beijing University of Chemical Technology,beijing 100029,china 2 beijing national laboratory for condensed matter physics,Institute of physics,chinese academy of sciences,beijing 100080,china College of Materials Science Engineering Beijing University of Chemical Technology Beijing 100029 China beijing national laboratory for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

We report here studies on the influence of oxygen pressure on the electroresis-tance behavior of La0.9Sr0.1MnO3 thin films fabricated by laser molecular beam epi-taxy. It was found that the film deposited at lower oxygen pressure shows larger c-axis parameter,higher resistance,and more distinct electroresistance. These results reveal that the electroresistance of manganite thin films can be tuned by the conditions of film fabrication.

关键词： La0.9Sr0.1MnO3 thin film electroresistance effect laser molecular beam epitaxy

superconductivity in Ti-doped iron-arsenide compound Sr_4Cr_(0.8)Ti_(1.2)O_6Fe_2As_2

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Science china(physics,Mechanics & Astronomy) 2009年第12期52卷 1876-1878页

作者： ZHU XiYu,HAN Fei,MU Gang,CHENG Peng,SHEN Bing,ZENG Bin & WEN HaiHu national laboratory for superconductivity,Institute of physics,chinese academy of sciences,beijing 100190,china beijing Na-tional laboratory for condensed matter physics,Institute of physics,chinese academy of sciences,beijing 100190,china 1. national laboratory for superconductivity Institute of Physics Chinese Academy of Sciences Beijing 100190 China 2. beijing national laboratory for condensed matter physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

superconductivity was achieved in Ti-doped iron-arsenide compound Sr4Cr0.8Ti1.2O6Fe2As2 (abbreviated as Cr-FeAs-42622). The X-ray diffraction measurement shows that this material has a layered structure with the space group of P4/nmm,and with the lattice constants a = b = 3.9003  and c = 15.8376 . Clear diamagnetic signals in ac susceptibility data and zero-resistance in resistivity data were detected at about 6 K,confirming the occurrence of bulk superconductivity. Meanwhile we observed a supercon-ducting transition in the resistive data with the onset transition temperature at 29.2 K,which may be induced by the nonuniform distribution of the Cr/Ti content in the FeAs-42622 phase.

关键词： iron-based superconductor high-temperature superconductor Perovskite

Recent progress in single chip white light-emitting diodes with the InGaN underlying layer

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 445-448页

作者： WANG XiaoLi, WANG XiaoHui, JIA HaiQiang, XING ZhiGang & CHEN Hong beijing national laboratory of condensed matter, Institute of physics, chinese academy of sciences, beijing 100080, china 1. beijing national laboratory of condensed matter Institute of Physics Chinese Academy of Sciences Beijing 100080 China

Tremendous progress has been achieved in white light-emitting diodes (LEDs). To further improve the quality of white light and simplify the fabrication process, a single chip white-light LED with the InGaN underlying layer (UL) was studied and fabricated. The turn-on voltage of this type of LED was 2.7 V, and the spectrum at a forward bias current of 20 mA was comprised of blue (443 nm) and yellow (563 nm) lights. The intensity ratio of blue to yellow light was almost constant with the in- creasing injection current in a certain scope, most important for the solid state illumination. The useful life test showed the light output level remained at a 90% light output level at the driving current of 40 mA after 300 h, meanwhile, the UV and blue LEDs combined with phosphor reached a 20% value after 144 h within 300 h.

关键词： GaN InGaN white light LED MOCVD

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) bulk metallic glass up to 24 GPa

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Science china(physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1, 2 , ZHAN Zaiji 2 , LIU Jing 3 , YUN Jinku 1 , SUN Liling 2 , LIU Riping 1 , ZHANG Jun 2 & WANG Wenkui 1, 2 1. Key laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, china 2. center for condensed matter physics, Institute of physics, chinese academy of sciences, beijing 100080, china 3. BSRF, Institute of High Energy physics, chinese academy of sciences, beijing 100039, china 1. Key laboratory of Metastable Materials Science and Technology Yanshan University 066004 Qinhuangdao China 2. center for condensed matter physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 3. BSRF Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

The compression of a Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) is investigated at room temperature up to 24 GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.