Spin-to-charge conversion by spin pumping in sputtered polycrystalline Bi$_x$Se$_{1-x}$
Isabel C Arango, Alberto Anadón, Silvestre Novoa, Van Tuong Pham, Won Young Choi, Junior Alegre, Laurent Badie, Andrey Chuvilin, Sébastien Petit-Watelot, Luis E… 展开作者
Isabel C Arango, Alberto Anadón, Silvestre Novoa, Van Tuong Pham, Won Young Choi, Junior Alegre, Laurent Badie, Andrey Chuvilin, Sébastien Petit-Watelot, Luis E Hueso, Fèlix Casanova, Juan-Carlos Rojas-Sánchez
Topological materials are of high interest due to the promise to obtain low power and fast memory devices based on efficient spin-orbit torque switching or spin-orbit magnetic state read-out. In particular, sputtered polycrystalline Bi$_x$Se$_{1-x}$ is one of the materials with more potential for this purpose since it is relatively easy to fabricate and has been reported to have a very high spin Hall angle. We study the spin-to-charge conversion in Bi$_x$Se$_{1-x}$ using the spin pumping technique coming from the ferromagnetic resonance in a contiguous permalloy thin film. We put a special emphasis on the interfacial properties of the system. Our results show that the spin Hall angle of Bi$_x$Se$_{1-x}$ has an opposite sign to the one of Pt. The charge current arising from the spin-to-charge conversion is, in contrast, lower than Pt by more than one order of magnitude. We ascribe this to the interdiffusion of Bi$_x$Se$_{1-x}$ and permalloy and the changes in chemical composition produced by this effect, which is an intrinsic characteristic of the system and is not considered in many other studies.
Suppression of Spin Pumping Between Ni$_{80}$Fe$_{20}$ and Cu by a Graphene Interlayer
我们比较了坡莫合金Ni $_{80}$ Fe $_{20}$（Py）薄膜溅射到Cu（111）薄膜上的铁磁共振测量，在Py沉积之前通过化学气相沉积生长石墨烯（Gr）中间层。一个两个角度的溅射方法，确保既没有Gr也没有Py的样品制备过程中降解。我们发现预期的阻尼增强自旋泵的Py/Cu的情况下，没有检测到的增强Py/Gr/Cu的情况下。由于阻尼是敏感的自旋泵以外的影响，我们用磁力来验证，在Py的静磁性能的差异是不是负责的阻尼的差异。我们把Py/Gr/Cu中自旋抽运的抑制归因于Gr/Cu界面的大接触电阻。
Light and microwave driven spin pumping across FeGaB-BiSb interface
具有大自旋霍尔电导率的三维拓扑绝缘体（TI）已成为自旋电子学应用的潜在候选者。在这里，我们报告的自旋电荷转换在双层的非晶铁磁体（FM）Fe_{78} Ga_{13} B_{9}（FeGaB）和3-D TI Bi_{85} Sb_{15}（BiSb）激活两个互补的技术：自旋泵和超快自旋电流注入。直流磁化测量建立FeGaB薄膜的软磁特性，保持不变的FeGaB-BiSb的异质结构。宽带铁磁共振（FMR）研究表明，随着自旋角动量泄漏到TI层中，旋进磁化的阻尼增强，自旋混合电导值较大（5.03 x 10^{19} m^{-2}）。通过分析由反自旋霍尔效应在TI层上产生的磁场控制的双极直流电压，提取BiSb的自旋霍尔角和自旋扩散长度。由飞秒光脉冲诱导的太赫兹辐射测量得到的自旋抽运参数与铁磁共振结果一致。Kubo-Bastin公式和紧束缚模型计算揭示了TI膜的厚度依赖性自旋霍尔电导率，预测结果与实验数据非常吻合。我们的研究结果表明，室温沉积的非晶和多晶异质结提供了一个有前途的平台，创造新的自旋轨道扭矩器件。
Ferromagnetic interface engineering of spin-charge conversion in RuO$_2$
School of Physics Science and Engineering, Tongji University（同济大学物理科学与工程学院）；Interdisciplinary Center for Theoretical Physics and Information Sciences, Fudan University（复旦大学理论物理与信息科学交叉中心）；Anhui Provincial Key Laboratory of Magnetic Functional Materials and Devices, School of Materials Science and Engineering, Anhui University（安徽大学材料科学与工程学院磁性功能材料与器件安徽省重点实验室）；Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences（中国科学院上海微系统与信息技术研究所）
