We report the single crystal growth and characterization of the highest T c iron-based superconductor SmFeAsO 1−x H x . Some sub-millimeter-sized crystals were grown using the mixture flux of Na 3 As + 3NaH + As at 3.0 GPa and 1473 K. The chemical composition analyses confirmed 10% substitution of hydrogen for the oxygen site (x = 0.10), however, the structural analyses suggested that the obtained crystal forms a multi-domain structure. By using the FIB technique we fabricated the single domain SmFeAsO 0.9 H 0.10 crystal with the T c of 42 K, and revealed the metallic conduction in in-plane (ρ ab ), while semiconducting in the out-of-plane (ρ c ). From the in-plane Hall coefficient measurements, we confirmed that the dominant carrier of SmFeAsO 0.9 H 0.10 crystal is an electron, and the hydride ion occupied at the site of the oxygen ion effectively supplies a carrier electron per iron following the equation: O 2− → H − + e − .
Iimura, S., Muramoto, T., Fujitsu, S., Matsuishi, S., & Hosono, H. (2017). High pressure growth and electron transport properties of superconducting SmFeAsO 1−x H x single crystals. Journal of Asian Ceramic Societies, 5(3), 357–363. https://doi.org/10.1016/j.jascer.2017.06.009