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arXiv · 1004.3581

23Na and 75As NMR Study of Antiferromagnetism and Spin Fluctuations on NaFeAs Single Crystals

L. Ma·G. F. Chen·Dao-Xin Yao·J. Zhang·S. Zhang·T. -L. Xia·Weiqiang Yu
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Abstract

We report the $^{23}$Na and $^{75}$As NMR studies on NaFeAs single crystals. The structure transition temperature $T_S$ (55 K) and the spin density wave (SDW) transition temperature $T_{SDW}$ (40.5 K) are determined by the NMR line splits. The spin-lattice relaxation rates indicate that the spin fluctuations are strongly enhanced just below $T_S$ and drive a second order SDW transition. A fluctuating feature of the SDW ordering is also seen below the $T_{SDW}$. We further performed high-pressure NMR studies on NaFeAs, and found that the $T_{SDW}$ increases by $\sim$7 K and the magnetic moment increases by 30% under 2.5 GPa pressure.

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L. Ma, G. F. Chen, Dao-Xin Yao, J. Zhang, S. Zhang, T. -L. Xia, Weiqiang Yu. 2011-04-19. 23Na and 75As NMR Study of Antiferromagnetism and Spin Fluctuations on NaFeAs Single Crystals. https://doi.org/10.1103/physrevb.83.132501

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