Magnetic excitations in layered electride ${\mathrm{Y}}_2\mathrm{C}$ have been found by inelastic neutron scattering. We have observed weak but clear magnetic scattering around the wave number $Q=0$, but no magnetic order down to the lowest temperature measured (7 K). The imaginary part of the dynamical susceptibility deduced is well described by the Lorentz function of energy $E$ for each momentum $Q$. The width $\mathrm{\Gamma }\left(Q\right)$ of the Lorentzian is proportional to $Q(Q^2+{\kappa }^2)$ with ${\kappa }^{-1}\sim 4\AA$ at $T=7$ K. We have also found that with increasing $Q$ the magnetic form factor decays faster than that of a $4d$ electron in a single Y atom, which indicates a more extended magnetic moment in ${\mathrm{Y}}_2\mathrm{C}$. These results provide experimental evidence that the itinerant magnetism in ${\mathrm{Y}}_2\mathrm{C}$ originates from the anionic electrons that reside in the interlayers. The Curie-Weiss-like behavior of the magnetic susceptibility reported in ${\mathrm{Y}}_2\mathrm{C}$ is ascribed to the mode coupling effects of spin fluctuations.

中文翻译：

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准二维电子Y2C中层间电子诱导的磁性：非弹性中子散射研究

分层驻极体中的磁激发 ${\mathrm{ÿ}}_2\mathrm{C}$通过非弹性中子散射已经发现。我们已经观察到波数周围有微弱但清晰的磁散射$问=0$，但没有磁阶降到最低实测温度（7 K）。能量的洛伦兹函数很好地描述了动态磁化率的虚部$Ë$ 每个动量 $问$。宽度$\mathrm{\Gamma }（问）$ 洛伦兹的比例与 $问（{问}^2+{\kappa }^2）$ 与 ${\kappa }^{-\mathrm{1个}}〜4\mathrm{一种}$ 在 $Ť=7$ K.我们还发现随着 $问$ 磁性形状因子的衰减速度比 $4d$ 单个Y原子中的电子，这表明 ${\mathrm{ÿ}}_2\mathrm{C}$。这些结果提供了实验证据，证明了${\mathrm{ÿ}}_2\mathrm{C}$源于驻留在中间层中的阴离子电子。报告的磁化率类似于居里-魏斯行为${\mathrm{ÿ}}_2\mathrm{C}$ 归因于自旋波动的模式耦合效应。