Superconductivity at 22 K in Ir-doped CaFe2−xIrxAs2 single crystals Yanpeng Qi, Zhaoshun Gao, Lei Wang, Xianping Zhang, Dongliang Wang, Chao Yao, Chunlei Wang, Chengduo Wang and Yanwei Ma EPL, 96 4 (2011) 47005 Published online: 11 November 2011 DOI: 10.1209/0295-5075/96/47005