Successive phase transition from superconducting and spin-density-wave states in (Ca_6(Al, Ti)_4OyFe_2As_2 studied via ^<75>As and ^<27>Al NMR
Successive phase transition from superconducting and spin-density-wave states in (Ca_6(Al, Ti)_4OyFe_2As_2 studied via ^<75>As and ^<27>Al NMR
复制标题
通过 ^<75>As 和 ^<27>Al NMR 研究 (Ca_6(Al, Ti)_4OyFe_2As_2) 中超导态和自旋密度波态的连续相变
DOI：
10.1103/physrevb.84.060502
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发表时间：
2011
影响因子：
3.7
通讯作者：
and J. Shimoyama
中科院分区：
文献类型：
--
作者：
T. Nakano;N. Fujiwara;S. Tsutsumi;H. Ogino;K. Kishio;and J. Shimoyama
通过 As 和 Al 核磁共振 (NMR) 在 (FeAs)(Ca(Al, Ti)O) 中发现了从超导 (SC) 相到反铁磁 (AF) 相的不寻常的连续相变，在 FeAs 平面之间插入了四个 (Al, Ti)O 层。尽管从Al谱中可以清楚地看到空间均匀的AF有序性，但有序矩非常小，低频波动受到很大抑制，这与现有的具有局域磁性元素的磷化物相反。此外，在整个温度范围内，两个原子核的涨落对温度 () 的依赖性非常相似。这些事实表明，Ti 和 Fe 轨道之间的某种杂化会在 FeAs 和 (Al, Ti)O 层内产生均匀的电子态，并伴随 SC 和 AF 跃迁。具有掺钛阻挡层的铁基磷族化物是第一个具有金属阻挡层的高化合物。
An unusual successive phase transition from superconducting (SC) to antiferromagnetic (AF) phases was discovered viaAs andAl nuclear magnetic resonance (NMR) in (FeAs)(Ca(Al, Ti)O) with four (Al, Ti)O layers intercalated between FeAs planes. Although the spatially uniform AF ordering is clearly visible fromAl spectra, the ordered moments are very small and the low-frequency fluctuation is much suppressed, contrary to existing pnictides with localized magnetic elements. Furthermore, the temperature () dependence of the fluctuation at both nuclei is very similar throughout the entire temperature range. These facts suggest that some hybridization between Ti and Fe orbitals induces a uniform electronic state within FeAs and (Al, Ti)O layers accompanied by the SC and AF transitions. The iron-based pnictide with Ti-doped blocking layers is the first high-compound having metallic blocking layers.