2011 Fiscal Year Final Research Report
Microscopic mechanism to determine strain dependence of critical current for Yttrium-based high Tc superconducting film
| Project/Area Number |
22760522
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Composite materials/Physical properties
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| Research Institution | High Energy Accelerator Research Organization (2011)
Kyoto University (2010) |
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Principal Investigator |
SUGANO Michinaka 大学共同利用機関法人高エネルギー加速器研究機構, 超伝導低温工学センター, 助教 (30402960)
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| Project Period (FY) |
2010 – 2011
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| Keywords | 臨界電流 / ひずみ効果 |
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| Research Abstract |
Yttrium-based superconducting film exhibits reversible effect of strain on critical current. However, the origin of this phenomenon has not been clarified. In this study, we succeeded in evaluating strain dependence of critical current in magnetic field for YBCO film without grain boundaries grown on SrTiO_3 single crystal substrate by means of a 4-point bending method. As a result, the peak of the critical current at a certain applied strain was confirmed for a single-crystalline film similar with the practical biaxially-textured polycrystalline film. This suggests that lattice deformation within a grain contributes to the reversible effect of strain on critical current as well as strain at the grain boundaries. In addition, change in internal strain under tensile loading was directly evaluated along a-anb b-axes for Gd-based superconducting films with different strain sensitivity to critical current using synchrotron radiation based on X-ray diffraction technique. This experiment reveals that GdBCO film with small strain sensitivity orients its[110] direction parallel to the loading axis and induced strain along the a-and b-axes is smaller than the other film in which a-and b-axis orients to the conductor axis and width. As a result, it was clarified that difference in crystal orientation of superconducting film can be one of the microscopic origins to determine strain dependence of critical current.
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