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arXiv · 1310.1143

In-plane spin excitation anisotropy in the paramagnetic phase of NaFeAs

Yu Song·Louis-Pierre Regnault·Chenglin Zhang·Guotai Tan·Scott V. Carr·Songxue Chi·A. D. Christianson·Tao Xiang·Pengcheng Dai
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Abstract

We use unpolarized and polarized inelastic neutron scattering to study low-energy spin excitations in NaFeAs, which exhibits a tetragonal-to-orthorhombic lattice distortion at $T_s\approx 58$ K followed by a collinear antiferromagnetic (AF) order below $T_N\approx 45$ K. In the AF ordered state ($T T_s$), spin excitations become more isotropic. Since similar magnetic anisotropy is also observed in the paramagnetic tetragonal phase of superconducting BaFe$_{1.904}$Ni$_{0.096}$As$_2$, our results suggest that the spin excitation anisotropy in superconducting iron pnictides originates from similar anisotropy already present in their parent compounds.

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Yu Song, Louis-Pierre Regnault, Chenglin Zhang, Guotai Tan, Scott V. Carr, Songxue Chi, A. D. Christianson, Tao Xiang, Pengcheng Dai. 2013-10-04. In-plane spin excitation anisotropy in the paramagnetic phase of NaFeAs. https://doi.org/10.1103/physrevb.88.134512

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