1307.5366 (Sangwon Oh et al.)

Microscopic coexistence of a two-component incommensurate spin density
wave with superconductivity in underdoped NaFe$_{0.983}$Co$_{0.017}$As    [PDF]

Sangwon Oh, A. M. Mounce, Jeongseop A. Lee, W. P. Halperin, C. L. Zhang, S. Carr, Pengcheng Dai, A. P. Reyes, P. L. Kuhns

We have performed $^{75}$As and $^{23}$Na nuclear magnetic resonance (NMR) measurements on a single crystal of NaFe$_{0.9835}$Co$_{0.0165}$As and found microscopic coexistence of superconductivity with a two-component spin density wave (SDW). Using $^{23}$Na NMR we measured the spatial distribution of local magnetic fields. The SDW was found to be incommensurate with a major component having magnetic moment ($\sim0.2\,\mu_B$/Fe) and a smaller component with magnetic moment ($\sim0.02\,\mu_B$/Fe). Spin lattice relaxation experiments reveal that this coexistence occurs at a microscopic level.

View original: http://arxiv.org/abs/1307.5366