标题： 垂直磁化的 [Pt/Co/W]n 多层结构中自旋轨道扭矩的线性增强以及体 Rashba 类自旋分裂的缺失 显示英文标题

标题： Linear Enhancement of Spin-Orbit Torques and Absence of Bulk Rashba-Type Spin Splitting in Perpendicularly Magnetized [Pt/Co/W]n Superlattices

摘要： 具有强自旋轨道力矩(SOTs)、低阻抗、强垂直磁各向异性(PMA)且同时具有良好集成兼容性的磁异质结构的发展对于高性能自旋电子存储和计算应用至关重要。 在这里，我们报告了可以溅射沉积在商业氧化硅基板上的对称性破坏的自旋轨道超晶格[Pt/Co/W]n的开发，并具有巨大的SOTs和9.2 Merg/cm3的强单轴PMA。 [Pt/Co/W]n超晶格的阻尼like和场like SOTs随着重复次数n的增加而线性增加，在n = 12时分别达到225%和-33%（比纯净极限Pt中的值大两个数量级）。 无论n的数值如何，阻尼like SOT的符号相反且幅度远大于场like SOT。这些结果阐明了在[Pt/Co/W]n超晶格中产生SOTs的自旋电流主要来源于自旋霍尔效应，而不是体 Rashba 类型的自旋分裂，为超晶格中的SOTs提供了统一的理解。 我们还展示了在低电流密度下，厚度大于50 nm的PMA [Pt/Co/W]12超晶格中的确定性切换。 这项工作确立了[Pt/Co/W]n超晶格作为超快、低功耗、长保持非易失性自旋电子存储和计算技术的有吸引力的材料候选。 显示英文摘要

摘要： The development of magnetic heterostructures with strong spin-orbit torques (SOTs), low impedance, strong perpendicular magnetic anisotropy (PMA), and good integration compatibility at the same time is central for high-performance spintronic memory and computing applications. Here, we report the development of the symmetry-broken spin-orbit superlattice [Pt/Co/W]n that can be sputtered-deposited on commercial oxidized silicon substrates and have giant SOTs, strong uniaxial PMA of 9.2 Merg/cm3. The dampinglike and fieldlike SOTs of the [Pt/Co/W]n superlattices exhibit a linear increase with the repeat number n and reach the giant values of 225% and -33% (two orders of magnitude greater than that in clean-limit Pt) at n = 12, respectively. The dampinglike SOT is also of the opposite sign and much greater in magnitude than the fieldlike SOT, regardless of the number of n. These results clarify that the spin current that generates SOTs in the [Pt/Co/W]n superlattices arises predominantly from the spin Hall effect rather than bulk Rashba-type spin splitting, providing a unified understanding of the SOTs in the superlattices. We also demonstrate deterministic switching in thicker-than-50-nm PMA [Pt/Co/W]12 superlattices at a low current density. This work establishes the [Pt/Co/W]n superlattice as a compelling material candidate for ultra-fast, low-power, long-retention nonvolatile spintronic memory and computing technologies.