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

H. Gretarsson: A. Lupascu, Jungho Kim, D. Casa, T. Gog, W. Wu, S. R. Julian, Z. J. Xu, J. S. Wen, G. D. Gu, R. H. Yuan, Z. G. Chen, N.-L. Wang, S. Khim, K. H. Kim, M. Ishikado, I. Jarrige, S. Shamoto, J.-H. Chu, I. R. Fisher, and Young-June Kim; Phys. Rev. B, 09/22/11.

Additional Authors: A. Lupascu, Jungho Kim, D. Casa, T. Gog, W. Wu, S. R. Julian, Z. J. Xu, J. S. Wen, G. D. Gu, R. H. Yuan, Z. G. Chen, N.-L. Wang, S. Khim, K. H. Kim, M. Ishikado, I. Jarrige, S. Shamoto, J.-H. Chu, I. R. Fisher, and Young-June Kim

Abstract:

We report a Fe Kβ x-ray emission spectroscopy study of local magnetic moments 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 (where A=K, Rb, and Cs). The moment size is independent of temperature or carrier concentration but varies significantly across different families. Specifically, all iron pnictide samples have local moments of about 1μB/Fe, while FeTe and K2Fe4Se5 families have much larger local moments of ∼2μB/Fe and ∼3.3μB/Fe, respectively. Our results illustrate the importance of multiorbital physics in describing magnetism of these compounds.