Proposal on a design concept of thin-film coated conductors using iron-based superconductors

本文研究了在MgO和（La，Sr）（Al，Ta）O_3双晶衬底上生长的掺钴BaFe_2As_2（BaFe_2As_2：Co）外延薄膜的双晶晶界（BGB）结的输运性质。在θ_GB ~9°附近，自场作用下的电流密度-电压特性由强耦合的GB行为向弱连接行为转变。这一结果表明，采用面内取向<9°的金属带衬底可以制备高性能的铁基超导薄膜涂层导体。

Transport properties of bicrystal grain boundary (BGB) junctions were studied in cobalt-doped BaFe_2 As_2 (BaFe_2 As_2 :Co) epitaxial films grown on [001]-tilt bicrystal substrates of MgO and (La, Sr)(Al, Ta)O_3 with misorientation angles θ_GB=3-45o. A transition from a strongly-coupled GB behavior to a weak-link behavior was observed in current density- voltage characteristics under self-field around θ_GB ~9°. This result clarifies that the high performance thin-film coated conductors using iron-based superconductors can be fabricated when we employ a metal-tape substrate with the in-plane orientation <9°.