High-pressure single-crystal neutron scattering study of magnetic and Fe   vacancy orders in (Tl,Rb)2Fe4Se5 superconductor
  The magnetic and iron vacancy orders in superconducting (Tl,Rb)2Fe4Se5 single-crystals are investigated by using a high-pressure neutron diffraction technique. Similar to the temperature effect, the block antiferromagnetic order gradually decreases upon increasing pressure while the Fe vacancy superstructural order remains intact before its precipitous disappearance at the critical pressure Pc = 8.3 GPa. Combined with previously determined Pc for superconductivity, our phase diagram under pressure reveals the concurrence of the block AFM order, the iron vacancy order and superconductivity for the 245 superconductor. A synthesis of current experimental data in a coherent physical picture is attempted. 
Feng Ye, Wei Bao, Songxue Chi, Antonio M. dos Santos, Jamie J.   Molaison, Minghu Fang, Hangdong Wang, Qianhui Mao Jinchen W...
cond-mat.supr-con