Manchester Centre for Mesoscience and Nanotechnology, Manchester M13 9PL, UK.
Nat Commun. 2013;4:2010. doi: 10.1038/ncomms3010.
Control of magnetism by applied voltage is desirable for spintronics applications. Finding a suitable material remains an elusive goal, with only a few candidates found so far. Graphene is one of them and attracts interest because of its weak spin-orbit interaction, the ability to control electronic properties by the electric field effect and the possibility to introduce paramagnetic centres such as vacancies and adatoms. Here we show that the magnetism of adatoms in graphene is itinerant and can be controlled by doping, so that magnetic moments are switched on and off. The much-discussed vacancy magnetism is found to have a dual origin, with two approximately equal contributions; one from itinerant magnetism and the other from dangling bonds. Our work suggests that graphene's spin transport can be controlled by the field effect, similar to its electronic and optical properties, and that spin diffusion can be significantly enhanced above a certain carrier density.
通过外加电压控制磁性对于自旋电子学应用是理想的。找到合适的材料仍然是一个难以实现的目标，迄今为止只发现了少数几个候选材料。石墨烯就是其中之一，由于其弱的自旋轨道相互作用、通过电场效应控制电子特性的能力以及引入顺磁中心（如空位和 adatoms）的可能性，它引起了人们的兴趣。在这里，我们表明石墨烯中 adatoms 的磁性是巡游的，可以通过掺杂来控制，从而可以打开和关闭磁性矩。人们广泛讨论的空位磁性具有双重起源，有两个大致相等的贡献；一个来自巡游磁性，另一个来自悬空键。我们的工作表明，石墨烯的自旋输运可以像其电子和光学特性一样通过电场效应来控制，并且在一定的载流子密度以上，自旋扩散可以显著增强。
