鉄系超伝導体SmFeAsOエピタキシャル薄膜への高濃度水素ドープに初めて成功し、48 Kの高温超伝導を観察

鉄系超伝導体SmFeAsOエピタキシャル薄膜への高濃度水素ドープに初めて成功し、48 Kの高温超伝導を観察

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フロンティア材料研究所 平松秀典准教授とSilvia Haindl特任准教授の共著論文

“Superconductivity at 48 K of heavily hydrogen-doped SmFeAsO epitaxial films grown by topotactic chemical reaction using CaH2

が、Phys. Rev. Materialsにweb掲載されました。(DOI:https://doi.org/10.1103/PhysRevMaterials.3.103401

 

<Abstract>

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(O1xHx). 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.