Superconductivity at 48 K of heavily hydrogen-doped SmFeAsO epitaxial films grown by topotactic chemical reaction using CaH2
Superconductivity at 48 K of heavily hydrogen-doped SmFeAsO epitaxial films grown by topotactic chemical reaction using CaH2
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DOI：
10.1103/physrevmaterials.3.103401
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发表时间：
2019-10-03
影响因子：
3.4
通讯作者：
Hosono, Hideo
中科院分区：
文献类型：
--
作者：
Matsumoto, Jumpei;Hanzawa, Kota;Hosono, Hideo
报道了在MgO单晶衬底上生长的掺氢SmFeAsO外延薄膜在48 K下的高临界温度（Tc）超导性。其关键工艺是脉冲激光沉积生长非掺杂SmFeAsO外延薄膜，然后在真空石英玻璃安瓿气氛下，用CaH 2粉末进行拓扑化学反应。基于我们已经开发的这种沉积后热退火处理，在SmFeAs（O 1-xHx）中实现了最大氢浓度x = 0.35。通过原子尺度微观结构观察直接实验证实了0位点处的无序氢取代。磁化强度测量验证了薄膜中高T-c超导性的整体性质。该方法将成为制备各种高质量氢氧化物外延薄膜的有效而通用的方法。
High-critical-temperature (T-c) superconductivity at 48 K is reported for hydrogen-doped SmFeAsO epitaxial films on MgO single-crystal substrates. The key processes are pulsed laser deposition to grow undoped SmFeAsO epitaxial films and subsequent topotactic chemical reaction using CaH2 powders under evacuated silica-glass ampule atmosphere. Based on this post-deposition thermal annealing treatment that we have developed, a maximum hydrogen concentration x = similar to 0.35 was realized in SmFeAs(O1-xHx). Disordered hydrogen substitution at 0 sites is experimentally confirmed directly by atomic-scale microstructural observations. Magnetization measurement validates the bulk nature of the high-T-c superconductivity in the films. This method will become an effective and general method to fabricate various high-quality oxyhydride epitaxial films.