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

研究了掺钴BaFe_2As_2(BaFe_2As_2：Co)外延薄膜中双晶晶界的输运特性。外延薄膜生长在[001]-倾斜的双晶衬底上，取向角θ_GB=3-45O。在θ_GB~9°附近的自场下，电流密度-电压特性发生了从强耦合的GB行为向弱连接行为的转变。这一结果表明，采用平面取向为lt；9°的金属带状衬底可以制备出高性能的铁基超导体薄膜涂层导体。

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°.