High-critical-temperature (Tc) 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=∼0.35 was realized in SmFeAs(O1–xHx). Disordered hydrogen substitution at O sites is experimentally confirmed directly by atomic-scale microstructural observations. Magnetization measurement validates the bulk nature of the high-Tc superconductivity in the films. This method will become an effective and general method to fabricate various high-quality oxyhydride epitaxial films.
First demonstration of heavy hydrogen-doping of an iron-based superconductor SmFeAsO epitaxial film and observation of high-Tc superconductivity at 48 K
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Published
(IIR Laboratory for Materials and Structures/Dr. Hidenori Hiramatsu and Dr. Silvia Haindl)
“Superconductivity at 48 K of heavily hydrogen-doped SmFeAsO epitaxial films grown by topotactic chemical reaction using CaH2”
Phys. Rev. Materials（DOI:https://doi.org/10.1103/PhysRevMaterials.3.103401）
＜Abstract＞