Iron chalcogenides, binary FeSe, FeTe and ternary FeTexSe1−x, FeTexS1−x and FeTe:Ox, are the simplest compounds amongst the recently discovered iron-based superconductors. Thin films of iron chalcogenides present many attractive features that are covered in this review, such as: (i) easy fabrication and epitaxial growth on common single-crystal substrates; (ii) strong enhancement of superconducting transition temperature with respect to the bulk parent compounds (in FeTe0.5Se0.5, zero-resistance transition temperature Tc0bulk = 13.5 K, but Tc0film = 19 K on LaAlO3 substrate); (iii) high critical current density (Jc ∼ 0.5 ×106 A cm2 at 4.2 K and 0 T for FeTe0.5Se0.5 film deposited on CaF2, and similar values on flexible metallic substrates (Hastelloy tapes buffered by ion-beam assisted deposition) with a weak dependence on magnetic field; (iv) high upper critical field (∼50 T for FeTe0.5Se0.5, Bc2(0), with a low anisotropy, γ ∼ 2). These highlights explain why thin films of iron chalcogenides have been widely studied in recent years and are considered as promising materials for applications requiring high magnetic fields (20–50 T) and low temperatures (2–10 K).
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机译:硫族元素铁,二元FeSe,FeTe和三元FeTexSe1-x,FeTexS1-x和FeTe:Ox是最近发现的铁基超导体中最简单的化合物。硫族铁化物薄膜具有许多吸引人的特性,这些特性在本篇综述中都有介绍,例如: (ii)与本体母体化合物相比,超导转变温度有很大提高(在FeTe0.5Se0.5中,零电阻转变温度Tc0 bulk sup> = 13.5 K,但Tc0 薄膜 sup> = 19 K(在LaAlO3衬底上); (iii)对于沉积在CaF2上的FeTe0.5Se0.5薄膜,在4.2 K和0 T下的临界电流密度高(Jc〜0.5×10 6 sup> A cm 2 sup>对磁场的依赖性较弱的柔性金属基底(Hastelloy磁带通过离子束辅助沉积来缓冲)的数值;(iv)较高的上临界场(FeTe0.5Se0.5,B c2 sub约为50 T >(0),各向异性低,γ〜2)这些亮点解释了为什么硫族硫铁化物薄膜近年来受到广泛研究,并被认为是需要高磁场(20–50 T)和低温(2–10 K)。
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