Revealing the dual nature of magnetism in iron pnictides and iron chalcogenides using x-ray emission spectroscopy

摘要

We report Fe K beta x-ray emission spectroscopy study of local magneticmoments in various iron based superconductors in their paramagnetic phases.Local magnetic moments are found in all samples studied: PrFeAsO,Ba(Fe,Co)2As2, LiFeAs, Fe1+x(Te,Se), and A2Fe4Se5 (A=K, Rb, and Cs). The momentsize varies significantly across different families. Specifically, all ironpnictides samples have local moments of about 1 $\mu_B$/Fe, while FeTe andK2Fe4Se5 families have much larger local moments of ~2$\mu_B$/Fe,~3.3$\mu_B$/Fe, respectively. In addition, we find that neither carrier dopingnor temperature change affects the local moment size.