高圧力下NMRによる鉄砒素系LaFeAsO_1－xH_xの磁気揺らぎと超伝導

抄録

In this article, a prototype of high-T_c iron-based superconductors, LaFeAsO_1－xH_x (0≤x≲0.6) was reviewed in the viewpoint of pressure-induced quantum phase transition and quantum criticality. The system undergoes an unusual phase transition from superconducting to antiferromagnetic (AF) phases upon heavily H doping. On applying a pressure of 4.0 GPa, the AF phase for x=0.6 disappears and a “bare” quantum critical point manifests. The present system offers a good opportunity for demonstrating the capability of the NiCrAl hybrid piston-cylinder pressure cell.