低温物理学报
（DIWENWULIXUEBAO）
第28卷 第2期
2006年5月
目 录
高温超导体中磁通涡旋薄饼运动的实验证明……………………………………………………………王唯先 张裕恒 (97)
三元硅化物CaAlSi的电-声子耦合和超导电性研究…………………………………………杜锦丽 马荣 李倩 刘楣 (102)
混合物理化学气相沉积法制备蓝宝石衬底外延MgB2薄膜性质的研究……丁莉莉 陈莉萍 李芬 冯庆荣 熊光成 (107)
Nd0.5Ca0.5Mn0.97Co0.03O3体系的超声研究………………………………………………刘毅 孔辉 郑世远 朱长飞 (112)
Mn位W掺杂对La0.3Ca0.7MnO3电荷有序相的破坏及磁性质影响…………………彭振生 郭焕银 毛强 严国清 (115)
正常金属-铁磁绝缘层-dx2-y2+idxy混合波超导结中的磁散射对隧道谱的影响…………………………………魏健文 (121)
高温超导磁体临界电流影响因素的研究………………………………………………张宏杰 励庆孚 宗军 董宁波 (129)
Y2BaCuO5粒子对顶部籽晶熔融织构YBCO微结构的影响………………………汪海英 徐克西 杨洋 邱静和 黄参 (130)
氩离子刻蚀对高温超导YBCO薄膜物理特性的影响……慕利娟 朴云龙 张晓平 赵永刚 魏斌 曹必松 江少林 (134)
镀金光纤光栅温度传感器的低温特性………………………………………………………………………郭明金 姜德生 (138)
晶粒尺寸对La0.83Na0.17Mn0.90Fe0.10O3磁性和输运性质的影响……………………………………………
刘艳梅 苗继鹏 王先杰 吕喆 隋郁 徐苗 黄晓莉 李玉 刘玉强 武高辉 苏文辉 (142)
钙钛矿锰氧化物(Nd1-xLax)0.5Ca0.5MnO3体系中的铁磁再入现象…………………………………………
王芳 方军 黄真 田建军 张勇 陈治友 陈敬林 (147)
一种新的高温超导磁体电磁结构优化设计方法……………………………………………………………王超 王秋良 (152)
低温下三角绝缘铁磁体的磁振子软化……………………………………………………………成泰民 鲜于泽 杜安 (156)
自旋三重态超导体结的直流Josephson电流………………………………………………………………………李晓薇 (160)
基于小波包分析的心磁信号消噪………………………………………………………陈 林 唐跃进 李敬东 梁伟 (164)
超导电子对波的长程相干性与AB效应…………………林德华 赵承均 胡炳全 黎松林 邹平 张中卫 杨德智 (168)
化学配比锰基钙钛矿输运特性研究………………………赵立峰 陈伟 商景林 缪菊红 余功奇 肖循 任光明 (172)
高温超导微波限幅器的研制……………………………………………………………宁俊松 张其劭 罗正祥 羊恺 (177)
低温环境下超导体微位移测量的研究…………………………………………………齐峰 雷沅忠 王秋良 余运佳 (182)
Bi-2223高温超导带材焊接接头电阻和过电流冲击性能实验研究…………………………………………
朱志芹 赵 祥 王银顺 惠 东 韩军杰 李晓航 (185)
低温功率器件驱动电路实验研究……………………………………………………………………………杨广辉 丘明 (191)
Al2O3衬底上生长的40.2 K转变温度的MgB2厚膜……………张开成 丁莉莉 庄承钢 陈莉萍 陈晋平 冯庆荣 (197)
CHINESE
JOURNAL OF LOW THEMPERATURE PHYSICS
VOL.28 NO.2 May, 2006
CONTENTS
Experimental
Demonstration of Vortex Pancake in High Temperature Superconductor……Wang Wei-Xian，ZHang Yu-Heng (101)
Electron-Phonon
Coupling and Superconductivity of Ternary Silicide CaAlSi………………………………………
Du
Jin-Li， Ma Rong， Li Qian， Liu Mei (106)
Growth
and Properties of Superconducting Epitaxial MgB2 Thin Film Fabricated
on Al2O3 Substrate by Hybrid Physical
Chemical
Vapor Deposition…Ding Li-Li，CHen Li-Ping，Li Fen，Yu
Zeng-qiang，Feng Qing-Rong，Xiong Guang-CHeng (111)
Ultrasonic
Study IN Nd0.5Ca0.5Mn0.97Co0.03O3………………Liu Yi， Kong Hui， ZHeng SHi-Yuan，
ZHu CHang-Fei (114)
Destruction
of Charge-Ordering Phase and Influence on Magnetic Property Induced by W Doping
at Mn Site of La0.3Ca0.7MnO3
……………………Peng ZHeng-SHeng，
Guo Huan-Gin， Mao Qiang， Yan Guo-Qing
(120)
Magnetic
Scattering Effect on the Tunneling Spectra in the Normal Metal-Ferromagnet Insulator-dx2-y2+idxy
Mixed Wave
Superconductor Junctions………………………………………………………………………………………Wei Jian-Wen (125)
Study
on the Factors Determining the Critical Current of Hts Magnets……………………………………………
ZHang
Hong-Hie，Li Qing-fu，Zong Jun，Dong
Ning-Bo (126)
Influence
of Y2BaCuO5 Particles on the Microstructure of Top-Seeded
Melt Textured YbCo Bulk…………………
Wang Hai-Ying，
Xu Ke-Xi， Yang Yang， Qiu Jing-He， Huang Shen
(133)
Effects
of Physical Characteristics on YbCo Hts Thin Film by Argon Ion Beam Etching……………………………
Mu
Li-Juan， Piao Yun-Long， ZHang Xiao-Ping，
ZHao Yong-Gang，Wei Bin，
Low
Temperature Properties of Fiber Bragg Grating Temperature Sensor with Plating
Gold…………………………
Guo
Ming-Jin， Jiang De-SHeng
(141)
The
Magnetic and Transport Properties of
La5/6Na1/6Mn0.90Fe0.10O3 is Influenced by Grain Size……Liu Yan-Mei，Miao
Ji-Peng，
Wang
Xian-Jie，Lü Zhe，Sui
Yu，Xu Miao，Huang Xiao-Li，Li Yu，
Liu Yu-Qiang， Wu Gao-Hui，Su Wen-Hui (146)
Occurrence
of Re-Entrant Ferromagnetic Transitions
In (Nd1-xLax)0.5Ca0.5MnO3
manganeses……………………
Wang Fang， Fang Jun， Huang ZHen，
Tian Jian-Jun，ZHang Yong，
CHen ZHi-You， CHen Jing-Ling
(151)
A
New Electromagnetic Optimization Design Method for Hts Magnets……………………Wang CHao， Wang Qiu-Liang (155)
The
softening of Magnon of Two-Dimensional Triangular Insulating Ferromagnetic under Low Temperature………
Tai-Min，
Xian Yu-Ze， Du An (159)
The
Dc Josephson Current In Spin-Triplet Superconductor Junctions…………………………………………Li Xiao-Wei (163)
Noise
Cancellation Techniques in Magnetocardiography Based on Wavelet Packet Method………………………
CHen
lin，Tang Yue-Jin，Li Jing-Dong，Liang Wei (167)
Long-Range
Coherence Effect of Superelectron-Pair Wave and Ab Effect………………………………………
Lin De-Hua，ZHao
CHeng-Jun，Hu Bing-Quan，Li Song-Lin，Zou
Ping，ZHang ZHong-Wei，Yang De-ZHi (171)
Transport
Properties of the Non-Stoichiomentic Manganites……………………………………ZHao Li-Feng， CHen Wei，
SHang
Jing-Lin， Wang Yong-Qiang， Miao Ju-Hong，Yu Gong-Qi， Xiao Xun， Ren Guang-Ming (176)
High
Temperature Superconductor Microwave Limiter'S Design…………………………………………………
Ning
Jun-Song， ZHang Qi-SHao， Lou ZHeng-Xiang， Yang Kai (181)
Experiments
on Measuring Superconductor'S Tiny Displacement Under Cryogenic Environment…………………
Qi Feng，
Lei Yuan-ZHong，Wang Qiu-Liang，Yu Yun-Jia (184)
Welding
Joint Resistance and Over Current Ac Impulse of High-Temperature
Superconducting Tape of Bi-2223……
ZHu ZHi-Qin， ZHao Xiang，
Wang Yin-SHun，Hui Dong，
Han Jun-Jie， Li Xiao-Hang
(190)
Experimental
Investigation of Gate-Driving Circuits at Cryogenic Temperature…………… Yang Guang-Hui， Qiu Ming (196)
40.2
K Critical Temperature of MgB2 Thick Film Deposited on Substrate of
Sapphire……………………………
ZHang Kai-CHeng，
Ding Li-Li， ZHuang CHeng-Gang，CHen
Li-Ping， CHen Chin-Ping， Feng Qing-Rong (200)
高温超导体中磁通涡旋薄饼运动的实验证明
王唯先 张裕恒
中国科学技术大学结构分析实验室，合肥 230026
为了验证高温超导体中涡旋薄饼运动的存在，我们设计了电流和电位引线分处样品不同表面的实验。实验结果表明，在这种电流电位引线配置下的E～j关系不同于刚性涡旋线运动所预期的E～j关系，由此支持了涡旋薄饼运动的存在。
关键词： 高温超导体, 涡旋薄饼, 涡旋线, 引线空间配置
PACC： 7460G
EXPERIMENTAL
DEMONSTRATION OF VORTEX PANCAKE
IN
HIGH TEMPERATURE SUPERCONDUCTOR
Wang Wei-Xian ZHang Yu-Heng
Structure Research Laboratory，University of Science and Technology of
China， Hefei，Anhui 230026
(Received 6 Junuary, 2006)
In order to
demonstrate the existence of the vortex pancake in high temperature
superconductor experimentally, a configuration in which the current and voltage
electrodes lies separately on the top and bottom surface is used. The E~j
relation obtained with this electrodes spatial configuration is different from
the expected E~j behavior of the stiff vortex line model. Thus,
the current results support the existence of the vortex pancake in high
temperature superconductor.
Keywords:
High temperature superconductor; vortex pancake; vortex line; electrodes
spatial configuration
PACC: 7460G
三元硅化物CaAlSi的电-声子耦合和超导电性研究
杜锦丽 马 荣 李 倩 刘 楣
东南大学物理系，南京 210096
应用全势线性缀加平面波方法计算新超导体CaAlSi的电子能带结构，用带心冻结声子法计算了声子频率及电-声子耦合常数，并讨论了它们的超导电性. 考虑到Al，Si原子分布的无序性和完全等价性，我们采用了双层超格子原胞模型，并考虑了低频B1g1声子频率的非谐性效应. 由此计算得到稳定的低频B1g1声子频率为110cm-1，对超导电性有较大的贡献的Cad 态电子与B1g1振动模式间的电-声子耦合常数为0.37. 我们的结果与用虚晶近似的结果是一致的. 并证明CaAlSi的超导电性可由中等耦合的BCS理论来解释.
关键词： 超导电性，能带结构，声子频率，电-声子耦合
PACC： 7400, 7125P，7430K
ELECTRON-PHONON
COUPLING AND SUPERCONDUCTIVITY OF TERNARY SILICIDE CaAlSi
Du Jin-Li Ma Rong Li Qian Liu Mei
Department of Physics, Southeast
University Nanjing, Nanjing 210096
(received 8 September,2005)
We use
FP-LAPW method to study the electronic band structure of new superconductor CaAlSi.
Phonon frequencies and electron-phonon coupling constant are calculated via
zone-center frozen phonon calculations. Considering the randomly distributed of
Al and Si atoms not only over the in-plane but also along the c direction，we chose the simplest double cell model
for the stable ternary silicide. Considering the anharmonicity of phonon
frequency, we obtain the phonon frequency of B1g1mode to be 110cm-1,
and the electron-phonon coupling constant between Ca d electron and B1g phonon
mode is 0.37, and λ= 0.73. The calculated results
are consistent with that by using the model of virtual-crystal approximation,
and proved that the superconductivity in CaAlSi can be well explained by the
standard BCS theory in the moderate electron-phonon coupling strength.
Keywords:
superconductivity, band structure, phonon frequency, electron-phonon coupling
PACC: 7400, 7125P，7430K
混合物理化学气相沉积法制备蓝宝石衬底外延MgB2薄膜性质的研究
丁莉莉 陈莉萍 李 芬 冯庆荣 熊光成
北京大学物理学院，人工微结构与介观物理国家重点实验室，北京 100871
我们用混合物理化学气相沉积（Hybrid physical-chemical vapor deposition简称为HPCVD）法在α-Al2O3（00l）衬底上原位制备了一批超导性能良好的外延MgB2超导薄膜样品. 用10％浓度的乙硼烷（B2H6）氢气混合气作为原料，研究了不同条件对MgB2薄膜沉积速率的影响. 在一定条件下制备了一批MgB2薄膜，厚度为200nm左右，样品的零电阻转变温度（Tc0）最高达到39K. X射线衍射分析的θ～2θ扫描表明， MgB2薄膜的晶粒都具有较好的C轴取向，对样品的（101）面Φ扫描结果显示MgB2薄膜晶格与衬底有很好的外延取向，取向关系为\[1010\] MgB2∥\[1120\] Al2O3. 由毕恩模型计算求得在5K和零场条件下，样品的临界电流密度Jc=9.8×106A/cm2. 这些结果表明HPCVD技术在MgB2外延薄膜原位制备方面有着很大的优势，从而有利于实现MgB2薄膜在电子器件方面的应用.
关键词： MgB2薄膜，X射线衍射图，SEM图， R～T曲线， M～H曲线
PACC：7475，7470，7430，7490，7470Y
GROWTH
AND PROPERTIES OF SUPERCONDUCTING EPITAXIAL MgB2 THIN FILM
FABRICATED ON Al2O3 SUBSTRATE BY HYBRID PHYSICAL CHEMICAL
VAPOR DEPOSITION
Ding Li-Li CHen Li-Ping Li Fen Yu Zeng-qiang
Feng Qing-Rong Xiong Guang-CHeng
School of physics and State Key Laboratory
of Artifical Microstructure and Mesoscopic Physics,
Peking University, Beijing 100871
(Received 9 November, 2005)
We have
fabricated several high quality epitaxial superconducting MgB2 thin
films onα-Al2O3（001）
substrate by using the hybrid physical chemical vapor deposition(HPCVD)
technique. Using B2H6 precursor gas of 10% concentration,
we studied the effect of different factors on the deposition rate of MgB2
thin films. Under definite conditions, we got a sae of superconducting MgB2
thin films with thickness of about 200nm, and the Tc0
of the best sample is up to 39.1K. X-ray diffraction pattern indicates that the
films possess a c-axis-oriented crystal structure perpendicular to the
substrate surface. Φscan of (101) MgB2 Reflections
reveals that the MgB2 thin films is in-plane epitaxial but the
lattice is rotated by 30°to match the hexagonal lattice
of sapphire. We obtain high critical current densities(Jc)=9.8×106A/cm2 at 5K under
self-field using Bean-Model calculating from the magnetic hysteresis
measurements. These indicate that the HPCVD technique is very promising for the
in-situ fabrication of MgB2 thin films and MgB2 electronic
devices.
Key
words: MgB2 thin films, X-ray diffraction patterns, SEM image, R~T
curve, magnetic hysteresis
PACC: 7475，7470，7430，7490，7470
YNd0.5Ca0.5Mn0.97Co0.03O3体系的超声研究
刘 毅 孔 辉 郑世远 朱长飞
中国科学技术大学材料科学与工程系先进功能材料与器件实验室，合肥 230026
贵州大学理学院, 贵阳 550003
系统研究了Nd0.5Ca0.5Mn0.97Co0.03O3单相多晶样品在低温下的电磁性质和超声特性. 超声测量结果表明，体系在低温下超声声速出现异常，超声声速从室温开始随着温度的降低逐渐减小，并在220K附近声速达到最小，其相对变化(ΔV/V)超过2％. 之后，随着温度的进一步降低，声速急剧硬化，其相对变化达到14.5%. 分析表明这是由于体系中电-声子相互作用导致的电荷有序态转变的结果，该电-声子耦合来源于Mn3＋的Jahn-Teller 效应. 同时，该体系在100K左右出现了金属-绝缘体转变同时伴随着铁磁相变，分析表明在低温下Co离子与Mn离子之间存在着铁磁交换作用，因此微量的Co掺杂会在反铁磁区域内形成部分铁磁小团簇，当铁磁团簇连通后，体系由反铁磁电荷有序态（AFM-CO）向铁磁金属态（FM-M）转变. 研究结果表明了样品在电荷有序相变温度TCO与金属-绝缘体转变温度TMI 之间（TMI<T<TCO）发生了铁磁金属态与反铁磁电荷有序态共存的相分离现象. TMI<T<TCO间的电荷输运遵循可变程跃迁（VRH）模型.
关键词: 超声声速，电荷有序态，Mn位掺杂，相分离
PACC: 6265, 7280G, 6320K
ULTRASONIC
STUDY IN Nd0.5Ca0.5Mn0.97Co0.03O3
Liu Yi Kong Hui ZHeng SHi-Yuan ZHu CHang-Fei
Laboratory of Advanced Functional
Materials and Devices, Department of Materials Science and Engineering,
University of Science and Technology of
China,Hefei 230026, People’s of Republic of China
School of Science, Guizhou University,
Guiyang 550003
(Received 14 November, 2005)
The
magnetization, resistivity and ultrasonic sound velocity have been measured in
polycrystalline Nd0.5Ca0.5Mn0.97Co0.03O3.
A charge ordering transition was observed near 220K in the temperature
dependence of magnetization and resistivity curves. It was found that the
longitudinal sound velocity shows a dramatic softening and stiffening around
charge ordering transition Tco. The ultrasonic
anomaly near Tco indicates the existence of strong
electron-phonon interaction in Nd0.5Ca0.5Mn0.97Co0.03O3
which originates from Jahn-Teller effect. Around TMI~100K,
a insulator-metal transition coincident with the FM transition was observed.
The transport mechanism of system in the temperature ranges TMI<T<
Tco obey the variable-range hopping (VRH) model.
Keywords:
ultrasonic sound velocity; charge ordering state; doping in the Mn site; phase
separation
PACC:
6265, 7280G, 6320K
Mn位W掺杂对La0.3Ca0.7MnO3电荷有序相的破坏及磁性质影响
彭振生 郭焕银 毛 强 严国清
材料研究室 宿州学院，安徽 宿州 234000
结构分析开放实验室 中国科学技术大学，安徽 合肥 230026
采用固相反应法制备了样品La0.3Ca0.7Mn1-xWxO3（x=0.00，0.12，0.15）. 通过测量样品的M～T曲线、M～H曲线和ESR曲线，研究了Mn位W掺杂对La0.3Ca0.7MnO3电荷有序相的破坏及磁性质的影响. 结果表明：当x=0.00时，在262K时形成电荷有序相（CO相）；当T＞262K时，表现为顺磁；当T＜190K时，表现为长程反铁磁（在AFM本底中存在少量FM成分），AFM/CO态共存；从262K（TCO）到190K，随温度降低在电荷有序态下从顺磁向反铁磁转变. 当x≈0.12时，在170K～180K残留CO相，而当x＝0.15时，CO相消失，体系存在一个 CO态融化过程，在极低温下存在顺磁-铁磁（PM-FM）相变.
关键词： 电荷有序，融化，磁性质，Mn位掺杂，钙钛矿氧化物
PACC: 7550L,7210
DESTRUCTION
OF CHARGE-ORDERING PHASE AND INFLUENCE ON MAGNETIC PROPERTY INDUCED BY W DOPING
AT MN SITE OF La0.3Ca0.7MnO3
Peng ZHeng-SHeng Guo Huan-Gin Mao Qiang Yan Guo-Qing
Materials Research Laboratory,Suzhou
College,suzhou,Anhui 234000
Structure Researsh Laboratory,University
of Science and Technology of China,Hefei 230026
(Received 10 October,2005; revised
manuscript received 28 October,2005)
The samples
of La0.3Ca0.7Mn1-xWxO3
(x=0.00,0.12,0.15) were prepared by the solid-state reaction method. We
studied the destruction of charge-odering phase and influence on magnetic
property induced by W doping at Mn site of La0.3Ca0.7MnO3 by measuring M～T curves、M～H curves and ESR curves of the samples.The
results showed that:When x=0.00,the charge-ordering(CO)phase forms at
262K;the sample exhibits paramagnetism when T＞262K；it
exhibits the coexistence of long-range
antiferromagnetism (there is a little FM composition in AFM
background)and the coexistence of AFM/CO state when T＜190K; and it transforms from
paramagnetism to antiferromagnetism in the charge-ordering state with the
temperature decreasing from 262K(TCO)to 190K.When x≥0.12，the
CO state melts, and there exists paramagnetism-ferromagnetism(PM-FM)transition
at extremely low temperature.
Key
words: charge ordering, melting, magnetic property, doping at Mn site,
perovskite oxide.
PACC: 7550L, 7210
正常金属-铁磁绝缘层-dx2-y2+idxy混合波超导结中的磁散射对隧道谱的影响
魏健文
淮阴师范学院物理系，淮安 223001
在正常金属-铁磁绝缘层-dx2-y2+idxy混合波超导隧道结中，考虑到铁磁绝缘层的磁散射和界面的粗糙散射效应,运用Bogoliubov-de Gennes(BdG)方程和Blonder-Tinkham-Klapwijk(BTK)理论，计算了隧道结中的准粒子传输系数和微分电导. 研究表明：（1）磁散射和界面粗糙散射均可以压低电导峰，其中磁散射能使电导峰滑移，而粗糙界面散射却能阻止这种滑移，且两散射的共同作用可抑制由混合波两序参数的幅值比不同所导致的电导峰滑移；（2）随铁磁层离超导表面距离的增加，隧道谱在零偏压处由凹陷变成了零偏压电导峰，继而又演化为凹陷中的中心峰；（3）当铁磁层离开超导表面有若干相干长度时，隧道谱中将呈现一些子能级谐振峰.
关键词： dx2-y2+idxy混合波超导体，磁散射，粗糙界面散射，微分电导
PACC：7450, 7475, 7210
MAGNETIC
SCATTERING EFFECT ON THE TUNNELING SPECTRA IN THE NORMAL METAL-FERROMAGNET INSULATOR-dx2-y2+idxy
MIXED WAVE
SUPERCONDUCTOR JUNCTIONS
Wei Jian-Wen
Department of Physics, Huaiyin Teachers
College, Jiangsu Huaian 223001
( Received 9 September,2005; revised
manuscript received 14 November,2005 )
Taking into
account the magnetic scattering and rough interface scattering effects of the
ferromagnet layer in the normal metal-ferromagnet insulator-dx2-y2+idxy
mixed wave superconductor tunnel junctions,using Bogoliubov-de Gennes(BdG)
eguation and Blonder-Tinkham-klapwjrk(BTK)theory, We calculate the
quasiparticle transport coefficients and the differential conductance. It is
found that: (1)both magnetic scattering and rough interface scattering can
abate the conductance peaks, in which the magnetic scattering can lead to a
splitting of the peaks but the rough interface scattering can resist the
splitting,and the joint effect of two scattering may suppress the splitting of
the conductance peaks that are caused by the different magnitude ratio of two
order parameter of mixed wave; (2)with increasing of the distance of the
ferromagnet layer away from the superconductor interface,the tunneling spectra
at zero-bias are changed from the dips to the peaks, then evolve the central
peaks in the dips; (3)the energy level resonant peaks in the tunneling spectra
are predicted if the ferromagnet layer is located several superconductor
coherence lengths away from the superconductor interface.
Keywords:
dx2-y2+idxy mixed
wave supercoductor, magnetic scattering, rough interface scattering,
differential conductance
PACC: 7450, 7475, 7210
STUDY
ON THE FACTORS DETERMINING THE CRITICAL CURRENT OF HTS MAGNETS
ZHang Hong-Hie Li Qing-fu Zong Jun Dong Ning-Bo
School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, 710049
Innova Superconductor Technology Co.,
Ltd., Beijing, 100176
The
critical current Ic is an important parameter to characterize
the Bi-2223 tape. The critical current is the function of the magnitude and the
direction to the tape of magnetic field at a certain temperature. It can be
measured by using the electric field criterion. The critical current of HTS
magnet is defined as the current at which the quench occurs. Due to the
difference of magnetic field in different position of an HTS magnet, the
calculation of the critical current for a magnet is complex. The inhomogeneous
performance of carrying current along the tape can also result in the difference
in critical current between the calculated result and the tested one. This
paper studies on the factors determining the critical current of an HTS magnet.
The local defect in the coil and the inhomogeneous distribution of the magnetic
field along the magnet are considered. The conclusions would be helpful to
design the HTS magnet and determine a safe operation current.
Keywords: HTS magnet, critical current, quench
PACS: 7460J
高温超导磁体临界电流影响因素的研究
张宏杰 励庆孚 宗 军 董宁波
西安交通大学电气工程学院，西安 710049
北京英纳超导技术有限公司，北京 100176
临界电流值是描述 Bi-2223高温超导带材性能的一个基本参数，在一定的温度条件下，Bi-2223高温超导带材的临界电流是带材所在位置磁场大小和磁场方向的函数，其短样的临界电流值可以通过四引线法测量，单根超导带材的自场很小，磁场对临界电流的影响可以忽略. 高温超导磁体的临界电流被定义成引发该磁体失超的最小电流，高温超导磁体的自场比单根超导带材的自场要大得多，磁体各个位置的磁场大小和方向各不相同，很难用理论的方法准确计算磁体的临界电流. 对于高温超导磁体而言，除了磁场的影响因素以外，绕制磁体所用的超导带材自身的均匀性也是影响其临界电流的一个重要因素. 本文对这两个因素进行探讨，并着重讨论高温超导带材自身的均匀性对临界电流大小的影响，本文的结论可以为高温超导磁体的设计、磁体绕制时带材的选择、磁体运行时安全工作电流的确定提供帮助.
关键词： 高温超导磁体，临界电流，失超
PACC： 7460J
Y2BaCuO5粒子对顶部籽晶熔融织构YBCO微结构的影响
汪海英 徐克西 杨 洋 邱静和 黄 参
上海大学物理系，上海 200444
本文主要研究了Y211相粒子在顶部籽晶熔融织构YBCO块材中的分布及其对材料超导特性的影响. 研究发现，在籽晶正下方，YBCO超导块材中的Y211粒子分布呈不均匀性. 样品在近籽晶处Y211粒子非常少，从样品顶部到样品底部Y211相粒子的容积率呈增大趋势. 由于Y123粒子和Y211粒子热膨胀系数存在差异，这种不均匀性导致了块材内部产生微裂纹，从而降低了磁悬浮力.
关键词： 熔融织构块材，Y211粒子分布，微结构
PACC: 7460, 7470
INFLUENCE
OF Y2BaCuO5 PARTICLES ON THE MICROSTRUCTURE OF TOP-SEEDED MELT TEXTURED YBCO
BULK
Wang Hai-Ying Xu Ke-Xi Yang Yang Qiu Jing-He Huang Shen
Physics Department of Shanghai
University, Shanghai 200444
(Received 26 September,2005; revised
manuscript received 19 December, 2005)
The
Y-211 particle distribution within the Melt-Textured Growth (MTG) YBCO bulk, as
well as its influence on the bulk superconducting properties, were
investigated. It was found that the Y-211 particle distribution within the bulk
appears in an inhomogeneous character, which present a gradually changed Y-211
particle density from the upper zone near the top-seed, with nearly little
Y-211 particles, to the lower part near the bottom of the bulk with a marked
Y-211 particles accumulation. Due to the thermal expansion difference for both
of the Y-123 bulk and Y-211 particles the micro-cracks in the bulk interior
were consequently brought about, which might result in the bulk levitation
force degradation observed in our experiments.
Key
words： MTG YBCO bulk，second phase particles distribution,
microstructure
PACC: 7460,7470
氩离子刻蚀对高温超导YBCO薄膜物理特性的影响
慕利娟 朴云龙 张晓平 赵永刚
魏 斌 曹必松 江少林
北京工业大学应用数理学院，北京 100022
清华大学物理系， 北京 100084
内蒙古科技大学理学院，包头 014010
本文研究了高温超导薄膜表面经氩离子不同程度刻蚀后其物理性能的变化，并采用离子刻蚀的方法设计制备了一个四节超导滤波器. YBa2Cu3O7－x（YBCO）薄膜表面经氩离子适当厚度刻蚀后的测试结果表明，薄膜的零电阻超导临界温度Tc随刻蚀时间适当的增加而提高，但过度刻蚀会带来电阻率的增大及转变宽度加宽. 经SEM观测，刻蚀后薄膜表面的颗粒减少，趋于平整，通过XRD分析，离子刻蚀使薄膜晶格常数c发生了变化，同时测得超导薄膜的临界电流密度Jc基本保持不变. 这一工作表明氩离子刻蚀对薄膜的氧含量及氧分布有一定的调控作用，并能提高薄膜的平整度，而且用此工艺制备出的超导滤波器显示出良好的微波特性，各项指标均达到了设计要求. 这些研究对高温超导薄膜在微波电路中的应用提供了有利的帮助.
关键词： 氩离子刻蚀，高温超导滤波器，零电阻Tc
PACC： 7430，7475
EFFECTS
OF PHYSICAL CHARACTERISTICS ON YBCO HTS THIN FILM BY ARGON ION BEAM ETCHING
Mu Li-Juan Piao Yun-Long ZHang Xiao-Ping ZHao Yong-Gang
Wei Bin Cao Bi-Song Jiang SHao-Lin
College of Applied Science, Beijing
University of Technology, Beijing
100022
Department of physics, Tsinghua
University, Beijing 100084
College of Science, Inner Mongolia
University of Science & Technology, Baotou 014010
(Received 22 November,2005; revised
manuscript received 8 December,2005)
The physic
properties of HTS film by Ar ion etching step for different thickness in the
surface was studied in this paper. Four probe measurement results indicated
that after the Ar ion etching step, the Tc of YBa2Cu3O7－x（YBCO）film increased, the resistivity was small
reduced when etching thickness less than 30nm, but the resistivity increased
and the width of the transportation became broad if in over etching step. SEM
shows the particles number and size were reduced and tend to flat when
increasing etching time. X-ray Diffraction shows the shift of the
characteristic (003) peaks and implies that the Ar ion etching can adjust to
the oxygen distribution. The current density Jc kept in the
same level and almost didn’t change after Ar ion etching
step. A 4-pole HTS filter was fabricated by using such Ar ion etching
film and the microwave properties is close to the simulating results. These
results are useful for the application of the HTS film in microwave circuits.
Keywords： Ar ion etching, HTS filter, Zero
resistance Tc
PACC: 7430, 7475
镀金光纤光栅温度传感器的低温特性
郭明金 姜德生
武汉理工大学光纤传感技术与信息处理教育部重点实验室,武汉430070
介绍了用相位掩膜方法制作光纤布拉格光栅（FBG）以及镀金的FBG温度传感器. 通过实验研究了-70℃ ～0℃之间的裸FBG和镀金FBG温度传感器的中心波长低温变化特性. 实验结果表明裸FBG和镀金FBG温度传感器的中心波长在-70℃ ～0℃的区间随温度线性变化，重复性较好并且几乎没有迟滞现象. 裸光纤布拉格光栅和镀金FBG温度传感器的温度灵敏系数KT 分别为0.0101nm/℃ 和0.0283 nm/ ℃. 并且它们的线性拟合度都超过0.999.
关键词: 导波与光纤光学，光纤布拉格光栅，相位掩膜，封装工艺，低温特性
PACC： 0720M, 4280L, 4281P
LOW
TEMPERATURE PROPERTIES OF FIBER BRAGG GRATING TEMPERATURE SENSOR WITH PLATING
GOLD
Guo Ming-Jin Jiang De-SHeng
Key Laboratory of Fiber Optic Sensing
Technology and Information Processing, Wuhan University of Technology，Ministry of Education，Wuhan 430070
(Received 28 November,2005;revised
manuscript received 15 February,2006)
Fiber Bragg
gratings (FBG) prepared in terms of a phase mask technique and the FBG
temperature sensor with plating gold were introduced. The center wavelength low
temperature properties of the bare Fiber Bragg grating and the FBG temperature
sensor with plating gold from -70℃
to 0℃ were researched by the
experiment. From the experimental results it could be seen that there is a very
good linearity and preferable repeatability between the
center wavelength shift of the bare FBG and the FBG temperature sensor with
plating gold and the temperature change from -70℃
to 0℃, and there is almost no
hysteresis effect. The sensitivities of the bare FBG and the FBG temperature
sensor with plating gold KT are 0.0101 nm/ ℃
and 0.0283 nm/ ℃ respectively. Their
pertinence coefficients are more than 0.999.
Key
words: Guided and fiber optics, optical fiber Bragg grating, phase mask, encapsulating
technique, properties of low Temperature
PACC： 0720M, 4280L, 4281P
晶粒尺寸对La0.83Na0.17Mn0.90Fe0.10O3磁性和输运性质的影响
刘艳梅1,2 苗继鹏1 王先杰1 吕 喆1 隋郁1 徐 苗1
黄晓莉1 李 玉1 刘玉强1 武高辉2 苏文辉1
1哈尔滨工业大学理学院凝聚态科学与技术研究中心，哈尔滨 150001
2哈尔滨工业大学金属基复合材料工程技术研究所，哈尔滨 150001
本文研究了纳米相和体相多晶样品La5/6Na1/6Mn0.90Fe0.10O3的结构、磁性和输运性质. XRD谱图表明两样品都是单相的钙钛矿结构. 随着晶粒尺寸的减小晶粒表面处的自旋无序增多，使居里温度降低,同时使自旋相关电子在晶界处的散射增强，提高了材料电阻率. 纳米粒子的尺寸效应提高了材料的低场磁电阻；晶粒表面自旋无序的增多使电子在晶粒表面的二阶隧道效应增强，提高了高场磁电阻效应. 零场电阻率的拟合结果也表明晶粒尺寸的减小使自旋无序增加.
关键词： 磁性，输运性质，双交换相互作用，二阶隧道效应
PACC: 7500,7530V, 7170G
THE
MAGNETIC AND TRANSPORT PROPERTIES OF La5/6Na1/6Mn0.90Fe0.10O3
IS INFLUENCED BY GRAIN SIZE
Liu Yan-Mei Miao Ji-Peng Wang Xian-Jie Lü ZHe Sui Yu Xu Miao
Huang Xiao-Li Li Yu
Liu Yu-Qiang Wu Gao-Hui Su Wen-Hui
Center for Condensed Matter Science and
Technology (CCMST), Department of Applied Physics,
Harbin Institute of Technology,
Harbin 150001
Center for Metal Matrix Composites
Engineering Technology, Harbin Institute of Technology, Harbin 150001
This paper presents the preparation of the nanometer phase and the bulk phase polycrystalline La5/6Na1/6Mn0.90Fe0.10O3 by sol-gel, and the investigation of their structure, magnetic and transport properties. XRD results at room temperature show that the structure of the samples is orthorhombic. The decreased grain size increases the surface spin disordered state and the resistivity which originates from the strengthened scatter of the spin correlation electron at the grain boundary, but reduces the Curie temperature. The lo