论文标题
153EU NMR揭示的EUFE2AS2中的磁去磁和二次磁相互作用
Magnetic detwinning and biquadratic magnetic interaction in EuFe2As2 revealed by 153Eu NMR
论文作者
论文摘要
在基于铁的超导体的列表状态下，双层形成通常会掩盖固有的，各向异性的，平面物理特性。依赖于典型的实验室磁场大于典型的实验室磁场，通常需要10--15 t以完全驱动样品。但是，最近发现一个非常小的平面内$ h _ {\ rm ext} \ sim $ 0.1 t足以使eufe $ _2 $中的nematic域$ _2 $作为$ _2 $。为了解释这种行为，已经提出了基于欧盟和FE旋转之间基于生物二级磁相互作用的微观理论。在这里，使用$^{153} $ eu核磁共振（NMR）测量值以下欧盟$^{2+} $订购温度，我们显示了在小平面内$ h _ {\ rm ext} $下detwinning的实验证据。我们的NMR研究还揭示了欧盟和FE旋转过程中角度的演变，该过程为系统中存在生物偶联而提供了第一个实验证据。
In the nematic state of iron-based superconductors, twin formation often obscures the intrinsic, anisotropic, in-plane physical properties.Relatively high in-plane external magnetic fields $H_{\rm ext}$ greater than the typical lab-scale magnetic fields 10--15 T are usually required to completely detwin a sample. However, recently a very small in-plane $H_{\rm ext} \sim$ 0.1 T was found to be sufficient for detwinning the nematic domains in EuFe$_2$As$_2$. To explain this behavior, a microscopic theory based on biquadratic magnetic interactions between the Eu and Fe spins has been proposed. Here, using $^{153}$Eu nuclear magnetic resonance (NMR) measurements below the Eu$^{2+}$ ordering temperature, we show experimental evidence of the detwinning under small in-plane $H_{\rm ext}$. Our NMR study also reveals the evolution of the angles between the Eu and Fe spins during the detwinning process, which provides the first experimental evidence for the existence of biquadratic coupling in the system.
