Synthesis of ErFeAsO-based superconductors by the hydrogen doping method Parasharam M. Shirage, Kiichi Miyazawa, Kunihiro Kihou, Chul-Ho Lee, Hijiri Kito, Kazuyasu Tokiwa, Yasumoto Tanaka, Hiroshi Eisaki and Akira Iyo EPL, 92 5 (2010) 57011 Published online: 04 January 2011 DOI: 10.1209/0295-5075/92/57011