75As nuclear magnetic resonance study of antiferromagnetic fluctuations in the normal state of LiFeAs

Abstract

We present a detailed study of 75As nuclear magnetic resonance Knight shift and spin-lattice relaxation rate in the normal state of stoichiometric polycrystalline LiFeAs. Our analysis of the Korringa relation suggests that LiFeAs exhibits strong antiferromagnetic fluctuations, if transferred hyperfine coupling is a dominant interaction between A 75 s nuclei and Fe electronic spins, whereas for an on-site hyperfine coupling scenario, these are weaker, but still present to account for our experimental observations. Density-functional calculations of electric field gradient correctly reproduce the experimental values for both A 75 s and L7 i sites. © 2010 The American Physical Society.