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Title: Novel tri-modal defect structure in Nb-doped MOCVD YBa2Cu3O7: A paradigm for pinning landscape control

Journal Article · · Nature Materials
OSTI ID:1059708

Immobilization of vortices, or flux pinning, is both an enduring scientific issue and one of the most important problems in optimizing high temperature superconductors (HTS) for commercial use. Here, we demonstrate a practical approach to the creation of a multi-modal flux pinning landscape in YBa2Cu3O7 (YBCO) films employing an industrially scalable metal organic chemical vapor deposition technique. Through controlled additions of Nb, we have achieved a novel distribution of crystallographic defects that immobilize (pin) vortices in the YBCO matrix. That is, with only the addition of a single dopant element, a tri-modal defect structure that threads through the YBCO matrix laterally (parallel to the ab planes of YBCO), vertically (parallel to the YBCO c-axis), and isotropically in the form of random spherical defects is induced. For optimally doped samples, the influence of these multi-modal nanocrystalline defect structures on the flux pinning properties manifests itself as a superior improvement in the critical current density (Jc) for all magnetic field orientations. The results demonstrate the possibility of achieving an ideal flux pinning landscape (from an orientation and strength viewpoint), which permits the design of HTS wires with fully-tuneable properties by processes suitable for large-scale manufacturing.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
OE USDOE - Office of Electric Transmission and Distribution
DOE Contract Number:
DE-AC05-00OR22725
OSTI ID:
1059708
Journal Information:
Nature Materials, Vol. 25, Issue 095013
Country of Publication:
United States
Language:
English

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