Superconductivity Enhancement in Fe3O4 Doped YBa2Cu3O7?em class="a-plus-plus">δ

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• 作者：Xueguang Dong (1)
  Pengfei An (2)
  Jing Zhang (2)
  Hongguang Zhang (3)
  Yongtao Li (1) (3)
  Hao Liu (1)
  Xiaopeng Ge (1)
  Qi Li (1)
  
• 关键词：Superconducting fractions ; EXAFS ; XANES ; Local structure disorder
• 刊名：Journal of Superconductivity Incorporating Novel Magnetism
• 出版年：2014
• 出版时间：March 2014
• 年：2014
• 卷：27
• 期：3
• 页码：693-699
• 全文大小：941 KB
• 作者单位：Xueguang Dong (1)
  Pengfei An (2)
  Jing Zhang (2)
  Hongguang Zhang (3)
  Yongtao Li (1) (3)
  Hao Liu (1)
  Xiaopeng Ge (1)
  Qi Li (1)
  
  1. Department of Physics, Southeast University, Nanjing, 211189, P.R. China
  2. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, P.R. China
  3. College of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210003, P.R. China
  
• ISSN：1557-1947

文摘

Flux pinning can lead to the enhancement of J c in superconductor. In order to study the effect of magnetic particles on superconductivity, the composites of (YBa2Cu3O7?em class="a-plus-plus">δ )0.98(Fe3O4)0.02 and (YBa2Cu3O7?em class="a-plus-plus">δ )0.98(α-Fe2O3)0.02 are synthesized with former sintered at different temperatures. The field-cooling measurements show that the T c of the samples has not changed. The superconducting properties are enhanced when the samples are sintered at high temperature (750??/sup>C), but suppressed for the samples without sintering or sintered at low temperature (350??/sup>C). Scanning electron microscopy images show that the doped Fe3O4 are diffused into intergrain sites. With the increase of sintering temperatures, the grain size of the sample grows up and the flux pinning, which leads to the enhancement of J c is formed by the addition of Fe3O4 nanoparticles. The extended X-ray absorption fine structure and X-ray absorption near edge structure experiments prove that after sintered at high temperatures the addition of Fe3O4 can induce disorder of local structures of YBa2Cu3O7?em class="a-plus-plus">δ . Also, the transition from the tetragonal phase to the orthorhombic phase is observed by the X-ray diffraction spectra. By the above analysis of experimental data, the enhancement of diamagnetic signal, which represents the superconducting properties can be attributed to the disorder enhancement of local structures and structural phase transition of the cuprates induced by the addition of Fe3O4.