检索结果-南通市图书馆

电流注入对La_(0.8)Te_(0.2.MnO_3/YBa_2.u_3O_(7-δ)双层结构中YBa_2.u_3O_(7-δ)超导电性的影响

在线全文

学校读者我要写书评

暂无评论

中国稀土学报 2004年第5期22卷 719-721页

作者：朱亚彬周岳亮戴守愚北京交通大学理学院物理系北京100044 中国科学院物理研究所光物理实验室中国科学院凝聚态物理中心北京100080

用电泳法在厚度为5mm×10mm×0.5mm的YBa2.u3O7-δ上沉积厚约70μm的La0.8Te0.2.nO3形成La0.8Te0.2.nO3/YBa2.u3O7-δ(F/S)双层结构。通过扫描电子显微镜观察双层结构剖面的形貌,采用标准的四引线法测量YBa2.u3O7-δ层的电阻特性。在F/... 详细信息

用电泳法在厚度为5mm×10mm×0.5mm的YBa2.u3O7-δ上沉积厚约70μm的La0.8Te0.2.nO3形成La0.8Te0.2.nO3/YBa2.u3O7-δ(F/S)双层结构。通过扫描电子显微镜观察双层结构剖面的形貌,采用标准的四引线法测量YBa2.u3O7-δ层的电阻特性。在F/S双层结构中通入1mA的注入电流,无论电流从S层流入F层(+Iinj),或者电流从F层流入S层(-Iinj),正常电阻均比未加注入电流时的电阻低;超导转变温度均比未加注入电流的转变温度高。

关键词：金属材料庞磁电阻超导电性注入电流稀土

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

在线全文

学校读者我要写书评

暂无评论

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 {2. and center of condensed matter {2., 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)/Ni79Fe2.(2. nm)/lr2.Mn78(12.nm)/Co75Fe2.(4 nm)/AI(0.8 nm)-oxide/Co75Fe2.(4 nm)/Ni79Fe2.(2. 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

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) bulk metallic glass up to 2. GPa

在线全文

学校读者我要写书评

暂无评论

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. {2. 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 {2. 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 Zr41Ti14Cu12.5Ni10Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. 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.

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

在线全文

学校读者我要写书评

暂无评论

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 {2., institute of {2. & center for condensed matter {2., chinese academy of sciences, 100080 beijing,{12. laboratory of optical {2. 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

The size effect on transport properties of colossal magnetoresistance materials La_(0.67)Ca_(0.33)MnO_3

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 251-257页

作者： LI PeiGang1,2.LEI Ming1,2.GUO YanFeng2.GUO Xi2.CHEN LeiMing2. TANG WeiHua1,2.SONG PengYun3 & CHEN JinPing3 1 Department of physics,center for Optoelectronics Materials and Devices,Zhejiang Sci-Tech University,Hangzhou 310018,{2. 2.National laboratory for condensed matter physics,institute of physics,chinese academy of sciences,{12. 100080,{2. 3 Department of physics,Peking University,{12. 100875,{2. 1. Department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou 310018 China 2. National laboratory for condensed {2. physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 3. Department of physics Peking University Beijing 100875 China

High quality La0.67Ca0.33MnO3 (LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO3(100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2.and 1.5 μm,the insulator-to-metal transition temperature (TP) keeps un-changed compared with the film. For the micro-bridges with width of 1 μm,the TP shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm,the insulator-to-metal transition disappears. The magnetoresistance be-havior of these micro-bridges was studied,and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced.

关键词： colossal magnetoresistance pulsed electron deposition electron beam lithography electrical transport properties

Containerless solidification of Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(2..5) glass-forming alloy in drop tube

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2002年第20期47卷 1700-1703页

作者： LI Gong, SUN Liling & WANG WenkuiCollege of Material sciences and Engineering, Yanshan University, Qinhuangdao 066004, china {2. for condensed matter physics, institute of physics, chinese academy of sciences, beijing 100080, china National Microgravit Coll. of Mat. Sci. and Engineering Yanshan University Qinhuangdao 066004 China center for condensed {2. physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China National Microgravity laboratory Chinese Academy of Sciences Beijing 100080 China

Droplets of Zr41Ti14Cu12.5Ni10Be2..5 glass forming alloys with different sizes are solidified in a drop tube containerless processing. Glass transition behavior, crystallization kinetics, and the phase evolution during annealing of the Zr41Ti14Cu12.5Ni10Be2..5 glassy spheres are investigated. The experimental results indicate that the apparent activation energy of the glass transition (Eg=435.5 kJ/mol), and the activation energy of the main crystallization reaction (Ep1 = 2.9.6 kJ/mol) are obviously different from those of bulk glass samples prepared by water quenched (Eg=559.1 kJ/mol and Ep1=192.5 kJ/mol). The difference is discussed in the view point of the atomic configuration of the liquid state of the metallic glass and nucleation mechanism.

关键词： ZrTiCuNiBe alloy containerless processing activation energy drop tube.

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2001年第4期19卷 399-405页

作者： Zhen-hua Yuan De-yan Shen Ren-yuan Qian Polymer physics laboratory {2. for Molecular Science, institute of Chemistry chinese academy of sciences, beijing 100080 china chinese Acad Sci Inst Chem Ctr Mol Sci Polymer Phys Lab Beijing 100080 Peoples R China

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in the temperature region 74-80.5 degreesC around the glass transition temperature. The film specimen was drawn to yield point followed by unloading to zero stress, then the residual deformation was held constant; while the subsequent evolution of the stress was recorded. An induction period was found in the course of stress evolution followed by a stress step-increase. The induction period decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol.K, which is attributed to the time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than 74 degreesC, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity in the non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results are interpreted in terms of Perez' theological model of a series connected Hooks spring and a Voigt element consisting of a parallel connected elastic spring and a dashpot.

关键词： pre-yield deformation PET uniaxial drawing non-Hooke deformation viscoelasticity stress induced rubbery deformation

CeO_2.thin films grown on biaxially textured nickel(001)

在线全文

学校读者我要写书评

暂无评论

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 {2., institute of physics and center for condensed matter physics, chinese academy of sciences, beijing 100080, Ch laboratory of optical {2. 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 2.0 eV ion energy and 2.0 μA/cm\+2.ion current density.

关键词： CeO\-2 films biaxial nickel.

Studies of Structure Evolution of Nanostructured Hf_(11)Ni_(89) Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1998年第3期14卷 205-210页

作者： Zhenfu DONG and Lianmao PENG(beijing Lab. of Electron Microscopy, institute of physics and center for condensed matter physics,{2. academy of sciences, P.O.Box 2.2., beijing 100080, china)Ke LU and Zhuangqi HU(State Key Lab. for RSA, institute of Meta beijing Lab. of Electron Microscopy Institute of Physics and Center for Condensed Matter Physics Chinese Academy of Sciences P.O.Box 2724 Beijing 100080 China State Key Lab. for RSA Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. The structure evolution of the sample was studied by using X-ray difFraction (XRD), transmission electron microscopy (TEM), difFerential scanning calorimetry (DSC), resistivity and magnetothermal analysis. Upon heating, a second precipitation process of the Ni(Hf) phase prior to grain growth wa5 detected by means of both structural analysis and physical property measurements. The measurement results are discussed based on the relationship between microstructure and physical properties.

关键词： Studies of Structure Evolution of Nanostructured Hf Alloy Ni