Tokyo Tech News

Discovery of second magnetic ordering phase accompanying structural change in iron-based superconducting materials


Published: October 28, 2014


The Element Strategy Initiative for Electronic Materials Research Group at the High Energy Accelerator Research Organization's Institute of Materials Structure Science, together with Assistant Professor Soshi Iimura of the Materials and Structures Laboratory at the Tokyo Institute of Technology, and Professor Hideo Hosono and Associate Professor Satoru Matsuishi, of the Materials Research Center for Element Strategy at the Tokyo Institute of Technology, investigated the magnetic properties and structure of the iron-based superconducting material LaFeAs (O1-xHx) using a multi-probe method, and discovered that a new magnetic ordering phase appears accompanying fine changes in structure in areas where the hydrogen substitution concentration x exceeds 0.4. This magnetic ordering phase adjoins the second superconducting phase in the same material published in 2012, and because it differs qualitatively from the previously known magnetic ordering phase in the host material (x = 0), it means that a new parent material has been found, and this is expected to be an important clue in understanding new superconductivity mechanisms.

These results were published in the online version of the English scientific journal "Nature Physics" on March 16, 2014 (local time).

New  Phase Diagram in LaFeAsO1-xHx

Fig. 1 New Phase Diagram in LaFeAsO1-xHx


M. Hiraishi, S. Iimura, K. M. Kojima, J. Yamaura, H. Hiraka, K.Ikeda, P. Miao, Y. Ishikawa, S. Torii, M. Miyazaki, I. Yamauchi, A. Koda, K. Ishii, M. Yoshida,J. Mizuki, R. Kadono,R. Kumai, T. Kamiyama, T. Otomo, Y. Murakami, S. Matsuishi and H. Hosono
Title of original paper:
Bipartite magnetic parent phases in the iron oxypnictide superconductor
Nature Physics

Further information
Professor Hideo Hosono
Frontier Research Center / Materials Research Center for Element Strategy