Microstructure of YBCO Superconducting Film on Metal Substrate with YSZ Buffer Layer

ＭｉｃｒｏｓｔｒｕｃｔｕｒｅｏｆＹＢＣＯＳｕｐｅｒｃｏｎｄｕｃｔｉｎｇＦｉｌｍｏｎＭｅｔａｌＳｕｂｓｔｒａｔｅｗｉｔｈＹＳＺＢｕｆｅｒＬａｙｅｒＷａｎｇＪｉｎｇ（王敬），ＬｉｕＡｎｓｈｅｎｇ（刘安生），ＳｈｉＤｏｎｇｑｉ（石东奇），ＷａｎｇＸｉａｏ...     

用分割靶法制备Y_（1－x）Ho_xBa_2Cu_3O_（7－δ）超导薄膜

本文利用直流磁控溅射技术，在（１００）钇稳定的ＺｒＯ２基片上制备出ｃ轴取向很好的Ｙ１－ｘＨＯｘＢａ２Ｃｕ３Ｏ７－δ（０＜ｘ≤１）超导薄膜。实验中所用的靶材由ＹＢＣＯ和ＨＢＣＯ超导材料各一半组成。随着ＨＢＣＯ靶材到加热器距离的变化，钬的含量发生变化，当ｘ＝０．７（原子比），零电阻温度Ｔ∞＞８３Ｋ。     

Y_（1－x）Dy_xBa_2Cu_3O_（7－δ）（X＝0．03，0．05）

叙述了用双靶直流磁控溅射仪制备Ｙ１－ｘＤｙｘＢａ＿２Ｃｕ＿３Ｏ＿（７－６）（ｘ＝０．０３，０．０５）超导薄膜的工艺。按其工艺制备的薄膜Ｔｅ均大于８８Ｋ，随着ｘ值增加，Ｊ＿ｃ有上升趋势。ＸＲＤ、ＳＥＭ的结果表明镝掺杂膜有很好的ｃ轴取向。讨论了高温超导体钉扎机制。     

YBa_2Cu_3O_(7-x)-Nb_2O_5系超导体制备及结构

日本研究人员在950℃恒温24h,制成了掺Nb_2O_5的 YBa_2Cu_3O_(7-x)超导体,其冷却速率为5℃/min。在 Nb_2O_5≤0.5wt%范围内,当增加Nb_2O_5掺杂量时,超导体体密度及临界电流密度(77K,H=0T)分别增至5.80g/cm~3和437     

Role of Nd_2O_3 nanoparticles addition on microstructural and superconducting properties of YBa_2Cu_3O_(7–δ) ceramics

The effects of Nd_2O_3 nanoparticles addition on microstructure,transport and AC susceptibility properties of YBa_2Cu_3O_(7–δ)(Y123) superconductors were systematically investigated using X-ray diffraction(XRD),scanning electron micrograph(SEM),four point probe measurement and AC spectrometer.It was found that the added samples were predominant by Y-123 phase beside small amount of Y-211 and unreacted Nd_2O_3 secondary phases.All added samples preserved the orthorhombic structure similar to the pure sample and no orthorhombic-to-tetragonal transition occurred.The samples became more porous and their grain size significantly decreased with addition of Nd_2O_3.The addition of nano-Nd_2O_3 disturbed the grain growth of Y123,thus resulting in the degradation of superconducting properties of the samples.The superconducting transition temperature(Tc onset) of samples decreased from 92 K for x=0.0 to 78 K for x=1.0 wt.%,which could be attributable to oxygen vacancy disorder.From AC susceptibility result,the inter-and intra-granular loss peaks became wider and broader with increase of Nd_2O_3 addition due to the weakening of grains coupling.On the other hand,the inter-granular critical current density,Jcm,was found to increase with Nd_2O_3 addition and had the highest value at x=0.6,confirming that Nd_2O_3 nanoparticles acted as pinning centers in Y123 matrix.     

磁控溅射法制备YBa_2Cu_3O_(7-x)双面超导薄膜

采用大直径中空柱状阴极磁控溅射装置和筒形加热器制备了高质量YBa2 Cu3O7-x双面超导薄膜。使用衬底为 (0 0 1)LaAlO3和 (0 0 1)YSZ。双面超导薄膜零电阻温度TC=89～ 91K ,临界电流密度JC≥ 10 6A/cm2 (77K ,零场下 ) ,微波表面电阻RS<1mΩ(77K ,10GHz)。对不同氧氩比下制备的双面膜进行了性能的比较。当O2 ∶Ar =1∶2 .5 ,衬底温度在80 0℃时 ,制备出了高质量的双面超导薄膜。同时对双面超导薄膜进行了微结构分析。用制备的 2 5mm× 2 0mm双面膜研制成功中频滤波器 ,中心频率为 1 0 6GHz时 ,插损为 0 6 7dB。     

稀土超导材料YBa_2Cu_3O_(7-x)相结构分析

用Y_2O_3,CuO,BaCO_3粉末烧结制得了超导材料,并对该材料的微观结构进行了X射线衍射及透射电镜分折,确认在超导相晶体内存在有规则排列的氧空位。     

Investigation of Chemical Bond Properties and Mssbauer Spectroscopy in YBa_2Cu_3O_7

ＹＢａ2 Ｃｕ3Ｏ7,ｓｏ ｃａｌｌｅｄ 12 3ｃｏｍｐｏｕｎｄ ,ｉｓａｎｉｍ ｐｏｒｔａｎｔｈｉｇｈＴｃ ｏｘｉｄｅｓｕｐｅｒｃｏｎｄｕｃｔｏｒ[1] .Ｉｔｓｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｉｓｑｕａｓｉｐｅｒｏｖｓｋｉｔｅ (Ｆｉｇ .1)ｗｉｔｈａｒｅｇｕｌａｒｓｔａｃｋｉｎｇｏｆＢａａｎｄＹｌａｙｅｒｓｉｎｔｈｅｃ ｄｉｒｅｃｔｉｏｎ .Ｉｔｉｓｏｒｔｈｏｒｈｏｍｂｉｃ ,ｂｅｌｏｎｇｉｎｇｔｏｔｈｅＰｍｍｍｓｐａｃｅｇｒｏｕｐｗｉｔｈｏｎｅｆｏｒｍｕｌａｕｎｉｔｐｅｒｐｒｉｍｉｔｉｖｅｃｅｌｌ .Ｔｈｅｙｔｔｒ…     

Study on Morphology of Surface of Large Area YBCO Thin Films on Zr（Y）O_2 Substrate

ＳｔｕｄｙｏｎＭｏｒｐｈｏｌｏｇｙｏｆＳｕｒｆａｃｅｏｆＬａｒｇｅＡｒｅａＹＢＣＯＴｈｉｎＦｉｌｍｓｏｎＺｒ（Ｙ）Ｏ_２ＳｕｂｓｔｒａｔｅＷａｎｇＲｕｉｋｕｎ（王瑞坤），ＳｕｎＬｉｈｏｎｇ（孙丽虹），ＬｉｕＨｏｎｇｆｅｉ（刘鸿飞）ＷａｎｇＸｉａｏｐｉ?..     

γ一射线辐照对稀土复合氧化物La_（2－x）Sr_xFe_2O_（7－δ）改性

用ＸＲＤ、ＴＧ、ＩＲ和ｍｏｓｓｂａｕｅｒ技术，研究了γ－射线辐照对稀土夏合氧化物Ｌａ＿（２－ｘ）Ｓｒ＿ｘＦｅ＿２Ｏ＿（７－δ）（０．２≤ｘ≤１）粉料性能的影响。发现粉料经辐照后，其Ｆｅ一Ｏ键相互作用增强，非他学计量氧的减少量增大，高质异能移（Ｉ．Ｓ．）发生变化。证明了γ一射线辐照是一个还侯过程，γ一射线辐照可以改变粉料的性能。     

Influence of Y~(3 ) on Structure and Electrochemical Property of LiMn_2O_4

Influence of Y~(3 ) on Structure and Electrochemical Property of LiMn_2O_4     

Improvement of Coercive Force of(CoFe)_3O_4 by Doping Ce

ＩｍｐｒｏｖｅｍｅｎｔｏｆＣｏｅｒｃｉｖｅＦｏｒｃｅｏｆ（ＣｏＦｅ）_３Ｏ_４ｂｙＤｏｐｉｎｇＣｅＸｕＨａｎｊｉａｎｇ（徐汉江）；ＣｈｅｎＪｕｎｍｉｎｇ（陈俊明）（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＭｅｔａｌｌｕｒｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙ...     

Cu_x(Al_2O_3)_(1-x)颗粒膜的巨霍耳效应研究

在由磁性金属颗粒镶嵌在非磁金属或绝缘基体中而形成的两相非均匀颗粒系统中 ,当磁性金属的体积百分含量处于临界值时 ,体系的输运行为有许多奇异的现象。相继在在磁性金属 非磁金属和磁性金属 绝缘体系统中发现了巨磁电阻效应和隧道磁电阻效应 ;特别的在磁性金属 绝缘体系统中发现了反常霍耳效应的极大增强 ,称为巨霍耳效应。为了探讨颗粒体系的巨霍耳效应的机制 ,本文用离子束共溅射的方法制备了大约 1.5× 10 - 7m厚度的Cux(Al2 O3) 1 -x颗粒薄膜 ,研究了非磁金属 绝缘体体系 :Cu Al2 O3颗粒系统的巨霍耳效应 ,发现在量子渗流阈值时 ,霍耳电阻比正常金属高 2个数量级。     

Structure and Transport Properties in CMR Materials of La（1-x）2/3Ca1/3MnO3 with Rare Earth Vacancies

Samples of manganese oxides La（1-x）2/3Ca1/3MnO3（x 〈 0.10） with Lavacancy were prepared by standard solid-state reaction method. All the samples are single phase, with orthorhombic symmetry （Pnma ）, analyzed by XRD and with Rietveld Refinement. The effect of different La-site vacancies concentration on electronic transport of La（1-x）2/3Ca1/3MnO3 was investigated. The insulator-metal transition temperature （about 267 K） nearly remains unchanged with the increase of vacancy concentration, which indicates that small La-vacancy does not destroy the double exchange interaction. But the electronic resistance increases and MR value decreases with La-vacancy content x 〉 0.04. The maximum of the MR value （8 T） is about 220% at transition temperature （TMI）.     

Influence of annealing temperature on luminescent properties of Eu~(3+)/V~(5+) co-doped nanocrystalline Gd_2Ti_2O_7 powders

Nanosized Gd2(1-x)Eu2xTi2O7:yV5+ phosphors were prepared via sol-gel method and characterized with X-ray diffraction,Raman spectroscopy,diffuse reflectance spectra and photoluminescence spectra.Their PL properties were investigated as functions of the Eu3+ doping concentration and annealing temperature.The results indicated that the as-prepared samples showed a strong emission of Eu3+ under the irradiation of 303 nm.For Eu3+-doped Gd2Ti2O7,the orange emission at 586 nm was the strongest,which was correspond...     

真空电弧等离子体合成(BixSb1-x)2Te3纳米粉末材料

以单质Bi,Sb和Te粉末为原材料,通过真空电弧等离子体蒸发法合成了(Bi<,x>Sb<,1-x>)<,2>Te<,3>热电粉末材料.采用X射线衍射(XRD)、能谱分析(EDS),场发射扫描电子显微术(FE-SEM),透射电子显微术(TEM)和选区电子衍射(SAED)分析方法对(Bi<,x>Sb<,1-x>)<,2>Te<,3>粉末材料的物相结构、成分和形貌进行了表征.XRD图谱的3强衍射峰分别为(015),(1010)和(110),(Bi<,x>Sb<,1-x>)<,2>Te<,3>纳米粉末的XRD图谱与标准XPD图谱峰(49-1713)相对应,宽化的衍射峰表明了粉末的晶粒具有纳米尺度.能谱定量分析表明Bi和Sb的原子百分比分别为18.1%,20.3%,两者原子百分比之和为38.4%,Te的原子百分比是61.6%.场发射扫描电子显微分析表明纳米粉末颗粒尺寸比较均匀,粉末存在团聚现象,大多数粉末都呈椭球形.透射电子显微分析表明(Bi<,x>Sb<,1-x>)<,2>Te<,3>纳米粉末的平均粒径约为50 mm,粉末呈不规则的多面体结构,还有一些薄片状和棒状的结构,这与Bi<,2>Te<,3>基半导体化合物的高度各向异性是一致的.(Bi<,x>Sb<,1-x>)<,2>Te<,3>纳米粉末的选区电子衍射图表明每一个颗粒是由许多小晶核组成的,证明了颗粒是以纳米尺度生长.由于晶粒取向随机,且晶粒细小引起有许多衍射斑组成的衍射环的宽化,揭示了(Bi<,x>Sb<,1-x>)<,2>Te<,3>纳米粉末的多晶结构.     

Growth and optical properties of Pr~(3+):La_2CaB_(10)O_(19) crystal

Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J',oscillator strengths PJ,J',radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spect...