Enhanced anisotropic spin fluctuations below tetragonal-to-orthorhobic transition in LaFeAs (O_<1-X>F_X) probed by ^<75>As and ^<139> La NMR
Enhanced anisotropic spin fluctuations below tetragonal-to-orthorhobic transition in LaFeAs (O_<1-X>F_X) probed by ^<75>As and ^<139> La NMR
复制标题
通过 ^<75>As 和 ^<139> La NMR 探测 LaFeAs (O_<1-X>F_X) 中四方晶向正交晶相转变以下的各向异性自旋波动增强
DOI：
10.1103/physrevb.85.134408
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发表时间：
2012
影响因子：
3.7
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
Y. Nakai;et al.
报道了LaFeAs（OF）（，0.025和0.04）的As和La NMR结果.随着F掺杂量的增加，四方相到正交相的相变温度、反铁磁相变温度和内磁场逐渐降低。但在30 K时，α t突然被抑制到沿着很小的范围内，这与Ba（Fe，Co）As和BaFe（As，P）的Ba 122系统中有序相的连续消失不同。自旋-晶格弛豫速率的各向异性在和0.025的顺磁相中是恒定的（1.5），但在以下由于磁涨落的减慢而增强而突然增加。这表明四方到正交结构畸变通过磁弹性耦合和/或自旋-轨道相互作用增强了自旋空间中的各向异性。
As andLa NMR results for LaFeAs(OF) (, 0.025, and 0.04) are reported. Upon F doping, the tetragonal-to-orthorhombic structural phase transition temperature, antiferromagnetic transition temperature, and internal magnetic fieldare gradually reduced for. However, at,is abruptly suppressed to be 30 K along with a tiny, which is distinct from the continuous disappearance of the ordered phases in the Ba122 systems of Ba(Fe,Co)Asand BaFe(As,P). The anisotropy of the spin-lattice relaxation rate,, in the paramagnetic phase ofand 0.025 is constant (1.5) but increases abruptly belowdue to the enhancement ofby the slowing-down of magnetic fluctuations. This indicates that the tetragonal-to-orthorhombic structural distortion enhances the anisotropy in the spin space via magnetoelastic coupling and/or spin-orbit interaction.