论文标题
通过堆叠订单来设计TB/CO非磁性多层的自旋轨道扭矩效率和磁性特性
Engineering the spin-orbit torque efficiency and magnetic properties of Tb/Co ferrimagnetic multilayers by stacking order
论文作者
论文摘要
我们测量了由CO/TB层组成的合成铁磁体中的自旋轨道扭矩(SOT),电流诱导的开关(DW)运动,其在PT底层上生长的堆叠顺序不同。我们发现SOT,磁各向异性,补偿温度和SOT引起的开关对CO和TB的堆叠顺序以及与PT接触的元素高度敏感。我们的研究进一步表明,与CO接触时,结核病是一种有效的SOT发生器,因此可以调整其在堆栈中的位置以生成PT生成的扭矩添加剂。凭借最佳的堆叠和层厚度,阻尼状SOT效率可达到0.3,这是PT/CO双层预期的两倍以上。此外,尽管电流密度约为0.5-2*107a/cm2,但磁化强度仍可以轻松切换,尽管垂直磁各向异性屏障极高(最高为7.8 t)。有效的切换是由于大SOT和低饱和磁化的组合,原因是多层的铁磁特征。我们在没有任何外场的情况下观察到电流驱动的DW运动,这表明同型Néel-type DWS通过界面dzyaloshinkii-Moriya相互作用稳定。这些结果表明,过渡金属/稀土合成铁磁铁中的堆叠顺序在确定与旋转型应用相关的磁转运特性中起着重要作用。
We measured the spin-orbit torques (SOTs), current-induced switching, and domain wall (DW) motion in synthetic ferrimagnets consisting of Co/Tb layers with differing stacking order grown on a Pt underlayer. We find that the SOTs, magnetic anisotropy, compensation temperature and SOT-induced switching are highly sensitive to the stacking order of Co and Tb and to the element in contact with Pt. Our study further shows that Tb is an efficient SOT generator when in contact with Co, such that its position in the stack can be adjusted to generate torques additive to those generated by Pt. With optimal stacking and layer thickness, the dampinglike SOT efficiency reaches up to 0.3, which is more than twice that expected from the Pt/Co bilayer. Moreover, the magnetization can be easily switched by the injection of pulses with current density of about 0.5-2*107A/cm2 despite the extremely high perpendicular magnetic anisotropy barrier (up to 7.8 T). Efficient switching is due to the combination of large SOTs and low saturation magnetization owing to the ferrimagnetic character of the multilayers. We observed current-driven DW motion in the absence of any external field, which is indicative of homochiral Néel-type DWs stabilized by the interfacial Dzyaloshinkii-Moriya interaction. These results show that the stacking order in transition metal/rare-earth synthetic ferrimagnets plays a major role in determining the magnetotransport properties relevant for spintronic applications.