Volume 83, Number 1, July 2008
Article Number 17002
Number of page(s) 4
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 11 June 2008
EPL, 83 (2008) 17002
DOI: 10.1209/0295-5075/83/17002

Superconductivity and phase diagram in iron-based arsenic-oxides ReFeAsO$_{1 - \delta}$ (Re = rare-earth metal) without fluorine doping

Zhi-An Ren, Guang-Can Che, Xiao-Li Dong, Jie Yang, Wei Lu, Wei Yi, Xiao-Li Shen, Zheng-Cai Li, Li-Ling Sun, Fang Zhou and Zhong-Xian Zhao

National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences - P.O. Box 603, Beijing 100190, PRC

received 16 April 2008; accepted in final form 12 May 2008; published July 2008
published online 11 June 2008

Here we report a new class of superconductors prepared by high-pressure synthesis in the quaternary family ReFeAsO$_{1 - \delta}$ (Re = Sm, Nd, Pr, Ce, La) without fluorine doping. The onset superconducting critical temperature (Tc) in these compounds increases with the reduction of the Re atom size, and the highest Tc obtained so far is 55 K in SmFeAsO$_{1 - \delta}$. For the NdFeAsO$_{1 - \delta}$ compound with different oxygen concentration a dome-shaped phase diagram was found.

74.10.+v - Occurrence, potential candidates.
74.70.-b - Superconducting materials.

© EPLA 2008