A complete phase diagram of high Tc iron oxypnictide SmFeAsO1-xHx

Detailed knowledge of the phase diagram illustrating the superconducting (SC) and magnetic phases is essential for a deeper understanding of the physics in iron-based superconductors. Recently in the electron-doped LaFeAsO1$-$xHx [1], we found a two-SC-dome structure in 0.05 $\le $ x $\le $ 0.45 and another antiferromagnetism (AFM) with a large moment and unique magnetic structure in over-doped region x \textgreater 0.4 [2]. However, due to the lack of the phase diagram of the SmFeAsO1$-$xHx particularly in the over-doped region, the relation between the high-Tc superconductivity and the magnetism is still unclear. Here, we present a complete phase diagram of SmFeAsO1-xHx with x ranging from 0 to 0.82 revealed by neutron diffraction and heat capacity measurements. We discovered a new AFM in the over-doped region, and the magnetic structure was incommensurate and predominantly longitudinal spin density wave. In this talk, we show the x- and temperature-dependence of magnetic and crystal structures in detail. [1] S. Iimura, et al., Nat. Commun. 3, 943 (2012). \newline [2] M. Hiraishi et al., Nat. Phys. 10, 300 (2014).