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YBa2Cu3O7-δ/LaAlO3 (YBCO/LAO) 超导薄膜是通过热蒸发沉积方法制备的,实验中使用的Tl2Ba2CaCu2O8/LaAlO3 (TBCCO/LAO) 超导薄膜是通过直流磁控溅射方法制备的.通过分析两片超导薄膜的XRD谱计算出了两片超导薄膜内的应变,ΔCY=4.8483×10-3;ΔCT=8.5272×10-5,结果显示YBCO超导薄膜内的应变要大于TBCCO超导薄膜内的应变.另外,采用共面谐振技术研究这两片超导薄膜内的微波表面电阻随温度的变化,结果表明YBCO超导薄膜具有更大的微波表面电阻.分析和讨论了应变对超导薄膜微波表面电阻的影响. 相似文献
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本文用对靶溅射技术制备了La2/3Ca1/3MnO3/YBa2Cu4O8/La2/3Ca1/3MnO3薄膜.与YBCO单层薄膜相比,由于超导/铁磁系统中的磁性邻近效应,三层薄膜表现出较低的超导转变温度.薄膜的R~T测量曲线显示出超磁阻(CMR)效应和超导转变,预示着超导和铁磁特性共存于LCMO/YBCO/LCMO三文治结构. 相似文献
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超导薄膜所受的应力对其临界转变温度Tc具有重要的影响,研究应力对超导薄膜Tc的影响对获得更高Tc材料具有重要意义.本文采用溶胶-凝胶法,在LAO单晶基板上制备了Y2O3/YBCO薄膜,并研究了Y2O3缓冲层对不同厚度YBCO超导薄膜的临界转变温度的影响.研究发现,当YBCO薄膜厚度为90nm时,由于Y2O3和YBCO薄膜的晶格错配,在YBCO/Y2O3薄膜的a-b面内引入了压应力,增加了c轴的晶格常数,结果提高了YBCO薄膜的临界转变温度.当YBCO薄膜的厚度较大时(如230nm),由晶格错配引起的应力通过位错的形式得以释放,YBCO薄膜的Tc变化不大. 相似文献
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三氟乙酸盐金属有机物沉积(TFA-MOD)方法是制备YBa2Cu3O7(YBCO)超导薄膜最有应用前景的方法之一。采用快速前处理TFA-MOD的方法在LaAlO3单晶基片上生长YBCO薄膜并与常规的TFA-MOD方法进行对比研究。XRD分析表明用快速前处理TFA-MOD方法制备的YBCO薄膜的c轴取向一致性,没有常规的TFA-MOD制备的YBCO薄膜好。SEM的分析表明快速前处理TFA-MOD制备的YBCO超导薄膜表面有孔洞和YBCO(103)取向生长的晶粒,常规方法制备的YBCO薄膜表面比较光滑,孔洞较少。虽然较常规方法制备的薄膜的临界电流密度(JC)低,但超导电性能分析表明,快速前处理方法制备的YBCO薄膜JC达到1mA/cm2以上,且前处理时间大幅缩短,对于提高YBCO薄膜制备的效率非常有效。 相似文献
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MOD法在BaPbO_3/LaAlO_3上沉积YBa_2Cu_3O_(7-σ)层的研究 总被引:1,自引:0,他引:1
实验配制了一种新型的YBCO前驱溶液,经过旋转涂覆和适当的热处理工艺,在单晶LaAlO3(100)基底和以BaPbO3为缓冲层的LaAlO3基底两种结构上外延生长YBa2Cu3O7-σ(YBCO)超导层。XRD结果表明:在两种结构上均生长了单相的YBCO层,YBCO晶粒沿垂直于基底表面的c轴方向外延生长。这种择优性在以BaPbO3为缓冲层的YBCO结构中更加明显。SEM结果表明,在两种结构上均形成致密的YBCO层。 相似文献
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J. Du S. Gnanarajan A. Bendavid 《Physica C: Superconductivity and its Applications》2004,400(3-4):143-152
The effect of magnesium oxide (MgO) surface conditions on in-plane grain orientation and critical current density of epitaxial YBa2Cu3O7 (YBCO) films was systematically investigated. The MgO substrates were either “as received” or stored for some time, cleaned using different methods and lithographically prepared for our step-edge junction devices. The YBCO films were grown via reactive thermal co-evaporation by Theva, GmbH. The surface characterisation of MgO substrates was studied using X-ray photoelectron spectroscopy (XPS). The in-plane grain orientation of the YBCO films was studied by means of X-ray diffraction (XRD) φ-scan and the critical current density was measured for the XRD scanned samples. The surface condition of the MgO substrates was found to have a strong influence on the in-plane grain orientation and the critical current density of the YBCO films. The MgO substrates with a degraded or contaminated surface gave rise to 45° grain misorientation in YBCO films and reduced the critical current density. A final process step using a low energy Ar ion beam etching (IBE) of the MgO substrates prior to the YBCO film deposition was found effective in removing the in-plane grain misorientation and promoting the growth of perfectly aligned c-axis YBCO films. 相似文献
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Fabrication of YBCO/YSZ and YBCO/MgO thick films using electrophoretic deposition with top-seeded melt growth process
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Superconducting thick films were grown on single crystals MgO and YSZ by electrophoretic deposition with Y_2BaCuO_5(Y211) addition. YBCO thick films were then accomplished by sintering the precursor films above the peritectic temperature. Single crystals of MgO (3×3×0.5 mm^3) were used as top-seed to control crystal structure of the thick films. As shown by scanning electron microscopy, the morphologies of YBCO/YSZ and YBCO/MgO thick films are spherulitic texture and platelet type. The critical temperature is ~89 K for the YBCO/YSZ thick film; the onset transition temperature is 86.4 K and the transition width is ~3 K for YBCO/MgO thick film. The critical current densities (as determined by Bean model) are, in A/cm^2, 3870 (77 K) for YBCO/YSZ thick films and 2399 (77 K) for YBCO/MgO thick films, which are comparable to the best J_c reported of the thick films prepared by the same method. 相似文献
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YBa2Cu3O7-x(YBCO)膜存在“厚度效应”: 随着厚度增加, YBCO薄膜的临界电流密度下降, 尤其是YBCO薄膜的厚度超过1 μm时, 它的临界电流密度急剧下降. 本文在YBCO薄膜之间引入极薄的二氧化铈(CeO2)薄膜, 成功制备出结构为YBCO/YBCO/CeO2/YBCO的超导厚膜. 所制备的厚度为2 μm的YBCO膜临界电流密度为1.36 MA/cm2 (77 K, 自场), 其性能比相同厚度的纯YBCO膜有了较大幅度的提升. 研究表明CeO2薄膜起到了传递织构、松弛应力的作用. 相似文献
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R. Teranishi Y. Miyanaga K. Yamada N. Mori M. Mukaida M. Miura M. Yoshizumi T. Izumi M. Namba S. Awaji K. Watanabe 《Physica C: Superconductivity and its Applications》2010,470(20):1246-1248
Tin-compounds were doped into YBa2Cu3O7−δ (YBCO) films as pinning centers to enhance Jc in magnetic fields. YBCO films were grown by a metal organic deposition process using tri-fluoroacetates starting solutions. Tin-acetylacetonate salts were then dissolved into the starting solution as pinning centers. Jc of the YBCO films with tin-acetylacetonates were enhanced in all magnetic field angles. Transmission electron microscopy (TEM) and TEM-EDS (Energy Dispersive X-ray Spectroscopy) observations revealed the existence of tin-compound particles with the size of about 30 nm in the YBCO film. These nano particles were distributed randomly in the film and were considered to act as 3-dimentional pinning centers. 相似文献