The interface between a magnetic material and a heavy metal that has a large spin-orbit interaction is at the root of various spin-related phenomena. In this paper, we address the peculiar spin-dependent transport at a $\mathrm{Pt}/{\mathrm{Cr}}_2{\mathrm{O}}_3$ interface by exploring the origin of the nonlinear anomalous Hall effect (AHE) in $\mathrm{Pt}/{\mathrm{Cr}}_2{\mathrm{O}}_3$ bilayers. X-ray magnetic circular dichroism (XMCD) measurements show no appreciable magnetic moment at the interface originating from $\mathrm{Cr}$ 3d and $\mathrm{Pt}$ 5d orbitals, which could be associated with the AHE response. A possible interfacial magnetic moment M at the $\mathrm{Pt}/{\mathrm{Cr}}_2{\mathrm{O}}_3$ interface, assumed from the detection limit of the XMCD measurements, yields an anomalous Hall conductivity ($\sigma \mathrm{AHE}$) per unit net magnetic moment (M), −${\sigma }_{\mathrm{AHE}}$/M, of 0.57 ${\mathrm{V}}^{-1}$, which is extraordinary large compared with that for general magnetic materials. Together with first-principles calculations, the results suggest the possibility of an intrinsic AHE in the $\mathrm{Pt}/{\mathrm{Cr}}_2{\mathrm{O}}_3$ interface that does not rely on the net magnetic moment.

中文翻译：

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Pt / Cr2O3接口处的巨型异常霍尔电导率

磁性材料与自旋轨道相互作用大的重金属之间的界面是各种自旋相关现象的根源。在本文中，我们讨论了在$铂/{铬}_2{\mathrm{Ø}}_3$ 通过探索非线性异常霍尔效应（AHE）的起源 $铂/{铬}_2{\mathrm{Ø}}_3$双层。X射线磁圆二向色性（XMCD）测量表明，在界面处没有明显的磁矩源自$铬$3 d和$铂$5 d轨道，可能与AHE响应有关。可能的界面磁矩中号的$铂/{铬}_2{\mathrm{Ø}}_3$ 根据XMCD测量的检测极限假设的界面会产生异常的霍尔电导率（$\sigma \mathrm{AHE}$）每单位净磁矩（M），-${\sigma }_{\mathrm{AHE}}$/ M，为0.57 ${\mathrm{V}}^{-\mathrm{1个}}$，与一般磁性材料相比非常大。结合第一性原理计算，结果表明，在AHE中存在固有AHE的可能性。$铂/{铬}_2{\mathrm{Ø}}_3$ 不依赖于净磁矩的界面。