硅衬底上BSCCO高温超导材料的制备

研究了采用单靶控溅射在Ｓｉ（１００）衬底上生长ＹＳＺ（钇稳定的ＺｒＯ２）ＢＳＣＣＯ（铋锶钙铜氧）薄膜的工艺条件,包括生长温度,生长气氛,生长速率及氧化退化等。还研究了高温超导相的形成与生长温度的关系,并获得了超导膜临界温度为８２Ｋ的ＢＳＣＣＯ／ＹＳＺ／Ｓｉ兼容材料。     

YSZ／Si上溅射BSCCO高温超导薄膜的工艺参数优化

本文研究了利用ＹＳＺ膜作缓冲层Ｓｉ衬底上溅射ＢＳＣＣＯ高温超导薄膜的生长工艺，分析了生长条件对Ｂｓｃｃｏ高温超导相的影响，并提出了ＹＳＺ／Ｓｉ上制备相ＢＳＣＣＯ膜的工艺参数。     

ZrO_2双晶衬底上生长的YBaCuO超导薄膜晶界结显微结构研究

ＺｒＯ２双晶衬底上生长的ＹＢａＣｕＯ超导薄膜晶界结显微结构研究俞大鹏戴远东王世光胡晓东王守证熊光成连贵君王永忠张泽＊（北京大学物理系，北京１００８７１＊中科院北京电子显微镜实验室，北京１０００８０）在不同取向的双晶衬底上生长ＹＢａＣｕＯ超导薄膜（超导...     

YBCO／Y－ZrO＿2／（1120）蓝宝石多层膜超导材料的分析电镜研究

我们在具有Ｙ稳定的ＺｒＯ＿２（ＹＳＺ）层的蓝宝石上获得高质量的ＹＢａ＿２Ｃｕ＿３Ｏ＿７（ＹＢＣＯ）高温超导薄膜。在零磁场下，７７ｋ时，其临界电流密度达到１．６×１０￣６Ａ／ｃｍ￣２。本文确定了多层膜超导材料的取向关系。ＹＢＣＯ膜的（００１）面平行于ＹＳＺ过渡层的（１００）表面。ＹＳＺ层厚为２０ｎｍ。并且，由于Ｂａ自ＹＢＣＯ层的外扩散，ＹＳＺ层含有Ｂａ。尽管蓝宝石与ＹＳＺ层间的晶格铅配很大，由于ＹＳＺ层具有［１００］择优取向，仍能获得准单晶的ＹＢＣＯ薄膜。在ＹＢＣＯ薄膜中，观察到均匀分布的、微小尺寸的Ｙ＿２ＢａＣｕＯ＿５（２１１相）沉淀粒子，它们也有利于提高临界电流密度。     

电子通道技术在YBa2Cu3O7外延超导薄膜研究中的应用

本研究采用电子通道技术（ＥＣＰ）对单晶和双晶外延生长的ＹＢａ＿２Ｃｕ＿３Ｏ＿７（ＹＢＣＯ）超导薄膜的结构、取向和表面完好性作检测，并证实对衬底的预处理可改善外延超导薄膜的质量；还对ＹＢＣＯ／ＣｅＯ＿２／ＭｇＯ／ＳｒＴｉＯ３的双外延薄膜作研究。     

YSZ—Si上溅射BSCCO超导薄膜的二次溅射效应

本文对溅射高温超导薄膜的过程中所产生的二次溅射效应（Ｒｅｓｐｕｔｔｅｒ－Ｅｆｆｅｃｔ）作了较系统的理论分析，观察敢ＹＳＺ－Ｓｉ衬底上磁控溅射ＢＳＣＣＯ高温超导薄膜时二次溅射效应所产生的影响，并通过采用偏轴溅射代替轴溅射而有效地缓解了该效应。     

脉冲激光淀积高电流密度的YBCO超导带材

采用脉冲激光加辅助离子源的方法在长为６．０ｃｍ的ＮｉＣｒ合金基带上制备０．１３μｍ厚的Ｙ－ＺｒＯ２（ＹＳＺ）隔离层，再用脉冲激光在ＹＳＺ／ＮｉＣｒ带上制备１．５μｍ厚的ＹＢａ２Ｃｕ３Ｏ７－ｘ超导厚膜形成ＹＢＣＯ／ＹＳＺ／ＮｉＣｒ超导带材。实验测得在７７Ｋ，０Ｔｅｓｌａ下其临界电流密度为８．７５×１０４Ａ／ｃｍ２，超导转变温度为８８．６Ｋ。     

不锈钢基底高电流密度YBCO超导线材

室温下应用Ａｒ＋ 离子源辅助准分子脉冲激光沉积（００２）取向的ＹＳＺ（Ｙｔｔｒｉａ－ｓｔａｂｉｌｉｚｅｄ ｚｉｒｃｏ－ｎｉａ）过渡层薄膜于不锈钢基底上;基底加温至７５０℃,用准分子脉冲激光沉积高电流密度ＹＢＣＯ（ＹＢａ２Ｃｕ３Ｏ７－ ｘ） 高温超导线材。实验结果表明：ＹＢＣＯ 超导线材临界温度Ｔｃ ≥９０ Ｋ （Ｒ＝０）,临界电流密度Ｊｃ ≥１×１０６ Ａ／ｃｍ ２（７７ Ｋ,０ Ｔ）。     

用低温磁力显微镜观察YBa2Cu3O7—x超导薄膜中的涡旋

用低温磁力显微镜观察ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－ｘ）超导薄膜中的涡旋＠郑兆佳＠袁彩文￥武汉工业大学材料研究与测试中心￥美国德克萨斯大学（奥斯汀）物理系用低温磁力显微镜观察ＹＢａ２Ｃｕ３Ｏ７－ｘ超导薄膜中的涡旋郑兆佳袁彩文ＡｌｅｘｄｅＬｏｚａｎｎｅ（武汉工业...     

YBa2Cu3O7／PrBa2Cu3O7／SrTiO3超薄膜表面螺旋位错的研究

本文报道了用原子力显微镜（ＡＦＭ）研究的几种（ＹＢＣＯ）超薄膜的表面结构，这些膜分别生长在ＳｒＴｉＯ３（１００）基底，和具有厚度为４０ｎｍ的ＰｒＢａ２Ｃｕ３Ｏ７缓冲导的ＳｒＴｉＯ３基底上，ＹＢＣＯ超薄膜厚度范围为２．５ｎｍ－２５ｎｍ。在２．５ｎｍ厚的单层膜表面观察到了岛状结构，并在７．５ｎｍ厚的超薄膜表面首次观察到了台阶高度度不同的三种螺旋位错。同时还讨论了ＹＢＣＯ超薄膜的生长机理。     

Micro Solid Oxide Fuel Cells on Glass Ceramic Substrates

Miniaturized solid oxide fuel cells are fabricated on a photostructurable glass ceramic substrate (Foturan) by thin film and micromachining techniques. The anode is a sputtered platinum film and the cathode is made of a spray pyrolysis (SP)‐deposited lanthanum strontium cobalt iron oxide (LSCF), a sputtered platinum film and platinum paste. A single‐layer of yttria‐stabilized zirconia (YSZ) made by pulsed laser deposition (PLD) and a bilayer of PLD–YSZ and SP–YSZ are used as electrolytes. The total thickness of all layers is less than 1 µm and the cell is a free‐standing membrane with a diameter up to 200 µm. The electrolyte resistance and the sum of polarization resistances of the anode and cathode are measured between 400 and 600 °C by impedance spectroscopy and direct current (DC) techniques. The contribution of the electrolyte resistance to the total cell resistance is negligible for all cells. The area‐specific polarization resistance of the electrodes decreases for different cathode materials in the order of Pt paste > sputtered Pt > LSCF. The open circuit voltages (OCVs) of the single‐layer electrolyte cells ranges from 0.91 to 0.56 V at 550 °C. No electronic leakage in the PLD–YSZ electrolyte is found by in‐plane and cross‐plane electrical conductivity measurements and the low OCV is attributed to gas leakage through pinholes in the columnar microstructure of the electrolyte. By using a bilayer electrolyte of PLD–YSZ and SP–YSZ, an OCV of 1.06 V is obtained and the maximum power density reaches 152 mW cm⁻² at 550 °C.     

Microscopic and Nanoscopic Three‐Phase‐Boundaries of Platinum Thin‐Film Electrodes on YSZ Electrolyte

Agglomerated Pt thin films have been proposed as electrodes for electrochemical devices like micro‐solid oxide fuel cells (μ‐SOFCs) operating at low temperatures. However, comprehensive studies elucidating the interplay between agglomeration state and electrochemical properties are lacking. In this contribution the electrochemical performance of agglomerated and “dense” Pt thin film electrodes on yttria‐stabilized‐zirconia (YSZ) is correlated with their microstructural characteristics. Besides the microscopically measurable triple‐phase‐boundary (tpb) where Pt, YSZ and air are in contact, a considerable contribution of “nanoscopic” tpbs to the electrode conductivity resulting from oxygen permeable grain boundaries is identified. It is demonstrated that “dense” Pt thin films are excellent electrodes provided their grain size and thickness are in the nanometer range. The results disprove the prevailing idea that the performance of Pt thin film electrodes results from microscopic and geometrically measurable tpbs only.     

Thin‐Film Electrodes: Microscopic and Nanoscopic Three‐Phase‐Boundaries of Platinum Thin Film Electrodes on YSZ Electrolyte (Adv. Funct. Mater. 3/2011)

Agglomerated Pt thin films have been proposed as electrodes for electrochemical devices like micro‐solid oxide fuel cells (μ‐SOFCs) operating at low temperatures. However, comprehensive studies elucidating the interplay between agglomeration state and electrochemical properties are lacking. In this contribution the electrochemical performance of agglomerated and “dense” Pt thin film electrodes on yttria‐stabilized‐zirconia (YSZ) is correlated with their microstructural characteristics. Besides the microscopically measurable triple‐phase‐boundary (tpb) where Pt, YSZ and air are in contact, a considerable contribution of “nanoscopic” tpbs to the electrode conductivity resulting from oxygen permeable grain boundaries is identified. It is demonstrated that “dense” Pt thin films are excellent electrodes provided their grain size and thickness are in the nanometer range. The results disprove the prevailing idea that the performance of Pt thin film electrodes results from microscopic and geometrically measurable tpbs only.     

Rapid thermal annealing of zirconia films deposited by spray pyrolysis

Zirconia (8 mol% yttria) (YSZ) amorphous layers were deposited by spray pyrolysis on Si oxidized substrates and crystallized by rapid thermal treatment in a home-made halogen lamps furnace. Uniform films were obtained by depositing up to six layers, followed by the thermal treatment. X-ray analysis showed that the cubic phase is obtained during the initial stage of the annealing process. No significant differences with increasing annealing time nor interaction between the YSZ film and the substrate were observed. Ionic conduction in air, with activation energies comparable to those of bulk YSZ ceramics, was observed. The electrical characteristics of the films make them suitable for microelectronics applications.     

氧化锆热障陶瓷铁弹增韧行为的原位电镜研究

氧化钇稳定氧化锆陶瓷(YSZ)具有基于铁弹性的高温增韧行为,它应用于发动机叶片表面的热障涂层表现出优异的热循环耐久性和高温韧性.然而,随着对发动机性能进一步提升的需求,当前的YSZ陶瓷难以满足更为严苛的使役环境.因此对铁弹性能微观机理开展相关的研究,并提升其高温稳定性就显得十分重要.本文采用原位透射电镜技术,获得对单晶...     

Characteristics Measurements of HTS Tape with Parallel HTS Tapes

Many high temperature superconducting (HTS) tape manufactures make an effort to reduce the transport current loss of HTS tapes. The knowledge of critical current and self-field in an HTS tape is very useful to compute the transport current losses. The spatial distribution and magnitude of self-field are variable due to the neighboring materials. In this paper, the critical currents and the transport current losses of BSCCO and YBCO tapes with paralleled magnetic material (Ni tape) and/or diamagnetic material (BSCCO tape) are experimentally investigated to improve the AC loss properties. The critical currents of HTS tapes with paralleled Ni tape are slightly decreased and the transport current losses are markedly increased. However, the critical currents and transport current losses of HTS tapes with paralleled BSCCO tape have not current carrying are more improved than single HTS tape.     

Development of Joints Between Two Parallel SS-Laminated BSCCO/Ag HTS Tapes

Stainless-steel (SS)-laminated high-strength high-temperature superconductor (HTS) BSCCO tapes are now commercially available for different practical applications. These SS-laminated HTS tapes are tolerant to smaller winding diameters, and the pancake winding becomes much easier due to higher tensile strength. However, the joining of two parallel SS-laminated HTS tapes is more complicated because of their limitation in maximum temperature exposure. The joining between the pancakes however becomes resistive due to the SS-laminated layer. We have experimentally studied the performance of the bridge joint between two parallel SS-laminated BSCCO tapes with different numbers of cross bridges of two different types of BSCCO tape. The splices of both SS-laminated BSCCO tape and silver (Ag)-sheathed BSCCO tape have been used as cross bridges at the joint. The current–voltage $I$–$V$ characteristic curves of the joints were investigated at 77 K, which is liquid nitrogen temperature. Joint resistance has been estimated from the $I$– $V$ characteristic curve. The lowest joint resistance achieved at 77 K at self-field, with six bridges made of SS-laminated HTS tape, is 0.78 $mu Omega$, and the lowest joint resistance of six Ag-sheathed HTS bridges is 0.54 $muOmega$. The corresponding contact resistances are 0.402 and 0.27 $muOmegacdothbox{cm}^{2}$ for both types of joints.      

Influence of Oxygen Pressure on the Properties of Ni-Mn-Zn Ferrite Films on Silicon Substrate

Ni-Mn-Zn ferrite films were prepared on silicon substrate with CeO₂/YSZ (YSZ: yttria-stabilized ZrO₂) as buffer layer by pulsed laser deposition. The influence of oxygen pressure on the microstructures and magnetic properties of films were studied. It was shown that the film crystallinity, microstructure and soft magnetic properties were sensitive to the oxygen pressure. High quality film with preferred (311) orientation, uniform surface structure, high purity and excellent soft magnetic properties can be obtained at the oxygen pressure of 1 Pa. The saturation magnetization (M _s) is higher than 230 emu/cm³ with a coercivity (H _c) smaller than 30Oe, which is suitable to be used in high-frequency devices.