Abstract Novel nematic states as well remarkable superconducting properties were reported in iron-based superconductors. We synthesized high-quality single crystals of (Ba 1- x Rb )Fe 2 As close to the optimal composition ≈ 0.4, and have characterized normal state for pristine proton irradiated samples. The highest T c was found be ∼36.6 K A maximum critical current density 12 MA/cm achieved a ...