镍基合金上离子束辅助沉积双轴取向的YSZ膜—YBCO超导膜缓冲层

用双离子束辅助沉积（ＩｏｎＢｅａｍＡｓｉｓｔｅｄＤｅｐｏｓｉｔｉｏｎ，ＩＢＡＤ）方法在Ｎｉ－Ｃｒ合金上合成了具有（００ｌ）择优取向，平面双轴排列的ＹＳＺ膜（Ｙ２Ｏ３－ＺｒＯ２）作为ＹＢＣＯ超导膜缓冲层。辅助轰击离子束方向与衬底法线的夹角５４０左右时可获得最佳的（００ｌ）择优效果。８０００Ｃ高温退火后其结构有较大的改善。在其上用ＭＯＣＶＤ方法生长的ＹＢＣＯ膜的Ｔｃ＝８８Ｋ，Ｊｃ＝１０×１０４Ａ／ｃｍ２（０Ｔ，７７Ｋ），并且从Φ扫描的结果说明了ＹＳＺ缓冲层上ＹＢＣＯ膜的生长机制。     

TiO_2对ZrO_2－NiCr金属陶瓷烧结特性和相稳定性的影响

本文研究了ＴｉＯ２掺入对ＣａＯ稳定ＺｒＯ２（简称ＣａＳＺ－ＮｉＣｒ）金属陶瓷烧结特性的影响，测定了ＣａＳＺ－ＮｉＣｒ－ＴｉＯ２金属陶瓷烧结样品的密度和显微硬度，结果表明，ＴｉＯ２的掺入能提高ＣａＳＺ－ＮＩＣｒ金属陶瓷的烧结密度和显微硬度，对ＣａＳＺ－ＮｉＣｒ金属陶瓷有助烧结作用．金相观察表明，ＴｉＯ３的掺入改变了ＮｉＣｒ相在金属陶瓷中的形貌，说明了ＮｉＣｒ与ＣａＳＺ的浸润性有一定的改善．ＸＲＤ和ＥＰＭＡ分析结果显示，ＴｉＯ２偏聚在ＮｉＣｒ金属相中，不影响ＣａＳＺ的稳定性．     

TiO2对ZrO2—NiCr金属陶瓷烧结特性和相稳定性的影响

本文研究了ＴｉＯ２掺入对ＣａＯ稳定ＺｒＯ２（简称ＣａＳＺ－ＮｉＣｒ）金属陶瓷烧结特性的影响，测定了ＣａＳＺ－ＮｉＣｒ－ＴｉＯ２金属陶瓷烧结样品的密度和显微硬度，结果表明，ＴｉＯ２的掺入能提高ＣａＳＺ－ＮｉＣｒ金属陶瓷的烧结密度和显微硬度，对ＣａＳＺ－ＮｉＣｒ金属陶瓷有助烧结作用。金相观察表明，ＴｉＯ２的掺入改变了ＮｉＣｒ相在金属陶瓷中的形貌，说明了ＮｉＣｒ与ＣａＳＺ的浸润性有一定的改善。ＸＲＤ和Ｅ     

Sb_2O_3掺杂对YBa_2Cu_3O_（7－δ）超导性质的影响

研究了Ｓｂ２Ｏ３掺杂的多晶ＹＢａ２Ｃｕ２Ｏ７－δ超导体的超导转变温度和输运临界电流密度Ｊｃ（Ｂ）在磁场中的行为。测量了超导性能对该掺杂浓度的依赖关系。适当浓度的掺杂可使Ｊｃ至少提高一个数量级。对掺杂样品进行了扫描电镜微结构观测和Ｘ射线结构分析。     

Na掺杂对MTG-YBCO临界电流密度特性的影响

本文研究了Ｎａ掺杂对ＭＴＧ－ＹＢＣＯ（ＹＢａ２－ｘＮａｘＣｕ３Ｏｙ＋４０ｍｏｌ％Ｙ２ＢａＣｕＯ５ｘ＝０．０、０．１、０．２）生长织构及其超导性能的影响。适量Ｎａ的掺入有利于ＭＴＧ－ＹＢＣＯ沿（ａｂ）面的生长,改善晶体生长的宏观形貌。同时,掺Ｎａ后ＭＴＧ－ＹＢＣＯ试样的Ｔｃ,ｏｎ变化不大,但Ｔｃ,ｏｆｆ随掺杂量ｘ的增加而降低,即超导转变宽度△Ｔ增大。适量Ｎａ掺杂改善了ＭＴＧ－ＹＢＣＯ的临界电流密度特     

Sb2O3掺杂对YBa2Cu3O7—δ超导性质的影响

研究了Ｓｂ２Ｏ３掺杂的多晶ＹＢａ２Ｃｕ３Ｏ７－δ超导体的超导转变温度和输运临界电流密度Ｊｃ（Ｂ）在磁场中的行为。测量了超导性能对该掺杂浓度的依赖关系。适当浓度的掺杂可使Ｊｃ至少提高一个数量级，对掺杂样品进行了扫描电镜微结构观测和Ｘ射线结构分析。     

CeO2-Y2O3固体氧化物燃料电池的电化学性能

以Ｙ２Ｏ３掺杂的ＣｅＯ２为固体电解质,制备了电解质支撑的固体氧化物燃料电池。测定了Ｈ２－Ｏ２电池的电压－电流密度（Ｖ－Ｉ）和输出功率－电流密度（Ｐ－Ｉ）关系曲线。为抑制ＣｅＯ２基材料的电子导电性的影响,采用溶胶凝胶技术,在阳极与电解质间制备了一层１μｍ厚的ＹＳＺ薄膜,７５０℃时,电池开路电压由０．７３Ｖ上升到０．８２Ｖ,最大输出功率密度从３６ｍＷ／ｃｍ＾２增加到５４ｍＷ／ｃｍ＾２,增大５０％,证明ＹＳＺ阻挡膜确定能改善电池的电化学性能。     

高Tc超导材料微结构的透射电镜研究

报导了高Ｔｃ材料的透射电镜研究。结合材料的物理性能，对ＹＢａ２Ｃｕ３Ｏｘ中氧的含量及有序、ＹＢａ２Ｃｕ３Ｏｘ融熔织构材料和Ｂｉ２Ｓｒ２ＣａＣｕ２Ｏｘ／ＭｇＯ复合材料中的晶界，以及高Ｔｃ薄膜和多层膜的结构进行了分析。     

在不锈钢上电沉积烧结Cr2O3—Y2O3薄膜及其改性后的抗高温氧化性能

分别在Ｃｒ（ＮＯ３）３、Ｙ（ＮＯ３）３及二者混合溶液中以１Ｃｒ１８Ｎｉ９Ｔ９不锈钢为阴极，电沉积Ｃｒ（ＯＨ）３、Ｙ（ＯＨ）３及Ｃｒ（ＯＨ）３－Ｙ（ＯＨ）３复合薄膜，然后经烧生成Ｃｒ３Ｏ４－Ｙ２Ｏ３及其复合薄膜层。通过研究未沉积试样与具有不同配比的薄膜试样在高温下静态氧化行为及表面氧化膜形貌、组成等。来探讨１Ｃｒ１８Ｎｉ９Ｔｉ表面经Ｙ、Ｃｒ的氧化物改性后的抗高温氧化性能。     

在不锈钢上电沉积烧结Cr_2O_3－Y_2O_3薄膜及其改性后的抗高温氧化性能

分别在Ｃｒ（ＮＯ３）３、Ｙ（ＮＯ３）３及二者混合溶液中以１Ｃｒ１８ＮｉｇＴｉ不锈钢为阴极，电沉积Ｃｒ（ＯＨ）３、Ｙ（ＯＨ）３及Ｃｒ（ＯＨ）３－Ｙ（ＯＨ）３复合薄膜，然后经烧结生成Ｃｒ２Ｏ２－Ｙ２Ｏ３及其复合薄膜层。通过研究末沉积试样与具有不同［Ｃｒ３＋］和［Ｙ３＋］配比的薄膜试样在高温下静态氧化行为及表面氧化膜形貌、组成等，来探讨１Ｃｒｌ８Ｎｉ９Ｔｉ表面经Ｙ、Ｃｒ的氧化物改性后的抗高温氧化性能。     

High-Quality YBa2Cu3O7−x Films with CeO2/YSZ Buffer Layers on 2-Inch Si Wafers Deposited by Pulsed Laser

The pulsed laser deposition (PLD) process is shown for in situ reproducibly fabricating YBa₂Cu₃O_7?x (YBCO) superconducting films with yttrium-stabilized zirconia (YSZ) and CeO₂ buffer layers, nonsuperconducting crystalline YBa₂Cu₃O_7?x (YBCO*) passivation layer, and silver contact film on 2-inch silicon wafers. Variations of less than ±7% in film thickness have been obtained for this multilayer growth over the whole wafer. The YBCO films on 2-inch silicon wafers have homogeneous superconducting properties with zero resistance temperature T _c0 from 88.4 K to 88.9 K. and critical current density J _c at 77 K and zero field from 2.5 × 10⁶ to 7× 10⁶ A/cm². The YSZ, CeO₂ and YBCO layers grow epitaxially on silicon wafers. Full widths at half maximum (FWHMs) of (113) reflections of 40 nm thick YBCO layer from φ-scan patterns are only 1.71° and 1.85° corresponding to the center and edge of the wafer, respectively. These results are very promising for developing high-quality high-T _c superconducting devices on large-area silicon wafers.     

High Quality YBCO Film Growth on SrTiO_3-Buffered LaAlO_3 Substrate by Full Solution Method

A full solution method has been developed as a low cost process of YBa2Cu3OT-x （YBCO） coated conductor fabrication. In this study, highly biaxially textured SrTiO3 （STO） buffer layers were fabricated on LaAlO3 （LAO） single crystal substrates by sol-gel method using metal alkoxides as the staring precursor materials. High quality YBCO superconducting film was then fabricated on STO-buffered LAO substrate by trifluoroacetic metalorganic deposition （TFA-MOD） method. For the YBCO superconducting film, only （001） diffraction peaks can be detected by XRD （X-ray diffraction） analysis with no other phases detectable. Especially, Inplane texture of YBCO film is improved compared to that of STO buffer layer from phi scans analysis, which indicates the self-epitaxy phenomenon explained by considering interracial energy. STO and YBCO films both show c-axis oriented grains growth and have uniform surface microstructure. A critical transition temperature, TC （R=0） of 89.5 K and a critical current density of 2 mA/cm2 （77 K, self-field） were obtained for a 0.2μm thick YBCO film on STO-buffered LAO substrate. No reaction between YBCO and STO was detected by XRD analysis. This full solution process may provide a promising low cost fabrication route for YBCO coated conductors on metal tape.     

脉冲激光法制备涂层导体YBCO超导层的研究

报道了用脉冲激光沉积技术(PLD)在CeO2/YSZ/Y2O3/NiW衬底上连续制备YBCO超导层的研究结果。分析了衬底温度、薄膜厚度和退火时间分别对YBCO的织构、表面形貌及c轴晶格常数的影响。实验发现温度较低将导致a轴晶粒的生长,薄膜太厚将引起表面形貌变差,而YBCO薄膜c轴晶格常数随退火时间的增长而减小。最终得到了高质量的YBCO涂层导体,超导转变宽度(ΔTc)为1.6K,临界电流密度(Jc)达1.3MA/cm2(77K,SF)。     

High-Quality YBa2Cu3O7?x Films with CeO2/YSZ Buffer Layers on 2-Inch Si Wafers Deposited by Pulsed Laser

The pulsed laser deposition (PLD) process is shown for in situ reproducibly fabricating YBa₂Cu₃O_7–x (YBCO) superconducting films with yttrium-stabilized zirconia (YSZ) and CeO₂ buffer layers, nonsuperconducting crystalline YBa₂Cu₃O_7–x (YBCO*) passivation layer, and silver contact film on 2-inch silicon wafers. Variations of less than ±7% in film thickness have been obtained for this multilayer growth over the whole wafer. The YBCO films on 2-inch silicon wafers have homogeneous superconducting properties with zero resistance temperature T _c0 from 88.4 K to 88.9 K. and critical current density J _c at 77 K and zero field from 2.5 × 10⁶ to 7× 10⁶ A/cm². The YSZ, CeO₂ and YBCO layers grow epitaxially on silicon wafers. Full widths at half maximum (FWHMs) of (113) reflections of 40 nm thick YBCO layer from -scan patterns are only 1.71° and 1.85° corresponding to the center and edge of the wafer, respectively. These results are very promising for developing high-quality high-T _c superconducting devices on large-area silicon wafers.     

低氟MOD法制备Zr掺杂YBCO薄膜的研究

在金属有机盐沉积（MOD）法制备YBCO薄膜的工艺中, 采用无F的α甲基丙烯酸铜取代原来的三氟乙酸铜, 可以降低前驱溶液中大约50%的氟含量. 研究表明, 该方法大大缩短了YBCO前驱薄膜受热分解的时间, 仅为原来的1/7. 通过XRD、SEM分析发现, 该方法可以制备成分单一、具有良好立方织构的YBCO薄膜, 且薄膜表面平整致密, 没有裂纹, 临界温度(T_c)达到了90K左右, 77K、自场下的临街电流密度(J_c)达到了2.84MA/cm². 通过在制备的YBCO薄膜中引入6mol% 的 Zr元素掺杂, 有效地提高了YBCO薄膜在外加磁场下的超导性能.     

Influence of substrate temperature on the texture and superconducting properties of thin films of YBa2Cu3O7-x on (1 0 0) YSZ substrates prepared by glow discharge sputtering

Films of c-axis textured YBa2Cu3O7-x (YBCO) were grown on (1 0 0) oriented yttria stabilized zirconia substrates by high pressure glow discharge sputtering. The influence of substrate temperature on the texture and superconducting properties of the films is reported. X-ray pole figure analysis has shown that a c-axis orientation of the film normal to the substrate surface occurs at an optimized substrate temperature of 953 K. HREM investigation revealed that the deposited material nucleates and grows as YBCO with a large amount of stacking faults and with a few Y2BaCuO5 particles. A dominant cube-to-cube orientation relationship is found between the YBCO film and the substrate. This revised version was published online in August 2006 with corrections to the Cover Date.     

High-temperature superconducting dual-mode resonator on (100) MgO substrate

We report, for the first time to our knowledge, a clear resonant peak split in the range of 7.7–9.7 GHz in a perturbed dual-mode disk-type resonator (DMDR) made of YBa₂Cu₃O_7–x (YBCO) superconducting thin film on MgO substrate. Epitaxial YBCO superconducting thin films were grown on (100) MgO substrates by pulsed laser deposition technique. The critical temperature of superconducting thin film on MgO substrate was 85 K. Superconducting dualmode disk resonators were designed by microwave design software, EEsof, and patterned by photolithography and a wet-etch process. The unloaded quality factor (Q_UL) of the superconducting DMDR was found to be 1,312 at 77 K. We believe this type of DMDR can be utilized for dual-mode resonator-based filters for satellite communications.     

Cobalt disilicide buffer layer for YBCO film on silicon

The CoSi₂ films were used as buffer layers of YBCO/CoSi₂/Si(100), YBCO/ZrO₂/CoSi₂/Si(100) and YBCO/CeO₂/YSZ/CoSi₂/epi-Si/Al₂O₃ heterostructures in this work. Transition temperatures of YBCO films were obtained up to 86K for YBCO films deposited by laser ablation on the top of CeO₂/YSZ/CoSi₂/Si/Al₂O₃ structure. Local nucleation on the crystal defects of silicon, the phenomenon of lateral directed growth (DLG) and agglomeration of CoSi₂ phase are responsible for grain boundaries (GB) position in CoSi₂ layer and its roughness. The roughness was decreased using an additional Zr film on the top structure.     

Reel-to-Reel PLD Fabrication of YBCO Coated Conductor by Single and Multi-coating Processes

YBa₂Cu₃O_7?δ (YBCO) coated conductors have been fabricated on CeO₂/YSZ/Y₂O₃ buffered Ni-5at%W tapes by pulsed laser deposition (PLD) using the reel-to-reel process. A multi-coating process for YBCO film was employed, and single and multi-coating methods for YBCO films are compared. X-ray diffraction texture measurements showed good in-plane and out-of-plane crystalline orientations for the YBCO films. Magnetic measurements were carried out on the samples, and the critical current density as a function of the magnetic field was investigated. The results showed that the superconducting properties of YBCO films fabricated by the multi-coating process were better than those prepared by the single coating process.     

Dependence of Microstructure and <Emphasis Type="Italic">J</Emphasis><Subscript>c</Subscript> of YBCO Films on CeO<Subscript>2</Subscript> Cap Layers Deposited by Multi-plume PLD

In order to achieve high-performance YBa₂Cu₃O_7?x (YBCO)coated conductors (CCs) fabricated in industrial scale, it is necessary to enhance the transport properties and production speed of the CCs for use in various application forms. The transport performance of CCs depends upon the inner structure of the conductors, which make it important to analyze the microstructure and transport properties. The thickness of the buffer layer is a factor in improving speed. In this work, we deposited YBCO films on CeO₂ cap layers with different thicknesses ranging from 21 to 563 nm by multi-plume pulsed laser deposition (PLD) and investigated the dependence of the microstructure and superconducting properties of YBCO film on the thickness of CeO₂ films. The crystalline structure and surface morphology of YBCO films are systematically characterized by means of XRD, AFM, SEM and TEM. The critical current of YBCO film was measured by the conventional four-probe method at 77 K, in self-field. The results showed that the microstructure and superconducting performance of YBCO film were strongly dependent on the thickness of CeO₂ films. At the optimal CeO₂ layer thickness of 221 nm, the YBCO film exhibited a sharp in-plane and out-of-plane texture of full width at half maximum (FWHM) values of 1.5° and 2.4°, respectively, and smooth morphology of root mean square (RMS) value as low as 4.0 nm. The sharply biaxially textured YBCO films with the critical current density as high as 4.7 × 10⁶ A/cm² (77 K, in self-field) were obtained on CeO₂/MgO/Y₂O₃/Al₂O₃/C276 architecture.