van den Brink A, Vermijs G, Solignac A, Koo J, Kohlhepp J T, Swagten H J M, Koopmans B
Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands.
SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191 Gif-sur-Yvette, France.
Nat Commun. 2016 Mar 4;7:10854. doi: 10.1038/ncomms10854.
As the first magnetic random access memories are finding their way onto the market, an important issue remains to be solved: the current density required to write magnetic bits becomes prohibitively high as bit dimensions are reduced. Recently, spin-orbit torques and the spin-Hall effect in particular have attracted significant interest, as they enable magnetization reversal without high current densities running through the tunnel barrier. For perpendicularly magnetized layers, however, the technological implementation of the spin-Hall effect is hampered by the necessity of an in-plane magnetic field for deterministic switching. Here we interface a thin ferromagnetic layer with an anti-ferromagnetic material. An in-plane exchange bias is created and shown to enable field-free S HE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface.
随着首批磁性随机存取存储器逐渐进入市场，一个重要问题仍有待解决：随着磁比特尺寸的减小，写入磁比特所需的电流密度变得高得令人望而却步。最近，自旋轨道转矩，尤其是自旋霍尔效应，引起了人们的极大兴趣，因为它们能够在不通过隧道势垒施加高电流密度的情况下实现磁化翻转。然而，对于垂直磁化层，自旋霍尔效应的技术应用因确定性切换需要面内磁场而受到阻碍。在此，我们将一层薄铁磁层与一种反铁磁材料相连接。产生了面内交换偏置，并证明其能够实现垂直磁化的Pt/Co/IrMn结构在无磁场情况下由自旋霍尔效应驱动的磁化翻转。除了潜在的技术意义外，我们的实验还为铁磁/反铁磁界面处的局部自旋结构提供了更多见解。
