YBa2Cu3O7-δ/LaAlO3和Tl2Ba2CaCu2O8/LaAlO3高温超导薄膜内的应变对其微波表面电阻影响的研究

Strain effect on microwave surface resistance of YBa_2Cu_3O_(7-δ)/LaAlO_3 and Tl_2Ba_2CaCu_2O_8/LaAlO_3 high temperature superconducting thin films

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.

YBa2Cu3O7-δ （YBCO） thin films were prepared by thermal eoevaporation on （LaAlO3 ） LAO substrates, and 332 Ba2 CaCu2O8 （TBCCO） thin films were synthesized by magnetron sputtering method on LAO substrates. We obtained the strain from the results of XRD of the films,which had the values of ΔCY=4·8483×10^-3 and ΔCT=8·5272×10^-5 . We found that the strain in YBCO was larger than that in TBCCO. In addition, the curve of surface resistance of the films as a funttion of temperature was obtained by eoplanar resonator technique, which showed the resistance of YBCO was larger than that of TBCCO at the same reduced temperature. In the paper, we also analyzed the strain effect on the surface resistance of the films.