We have studied the Co layer thickness dependences of magnetocrystalline anisotropy (MCA), Dzyaloshinskii-Moriya interaction (DMI), and orbital moment anisotropy (OMA) in W/Co/Pt trilayers, in order to clarify their correlations with each other. We find that the MCA favors magnetization along the film normal and monotonically increases with decreasing effective magnetic layer thickness ($t_\mathrm{eff}$). The magnitude of the Dzyaloshinskii-Moriya exchange constant ($|D|$) increases with decreasing $t_\mathrm{eff}$ until $t_\mathrm{eff} \sim$1 nm, below which $|D|$ decreases. The MCA and $|D|$ scale with $1/t_\mathrm{eff}$ for $t_\mathrm{eff}$ larger than $\sim$1 nm, indicating an interfacial origin. The increase of MCA with decreasing $t_\mathrm{eff}$ continues below $t_\mathrm{eff}$ $\sim$ 1 nm, but with a slower rate. To clarify the cause of the $t_\mathrm{eff}$ dependences of MCA and DMI, the OMA of Co in W/Co/Pt trilayers is studied using x-ray magnetic circular dichroism (XMCD). We find non-zero OMA when $t_\mathrm{eff}$ is smaller than $\sim$0.8 nm. The OMA increases with decreasing $t_\mathrm{eff}$ more rapidly than what is expected from the MCA, indicating that factors other than OMA contribute to the MCA at small $t_\mathrm{eff}$. The $t_\mathrm{eff}$ dependence of the OMA also suggests that $|D|$ at $t_\mathrm{eff}$ smaller than $\sim$1 nm is not related to the OMA at the interface. We propose that the growth of Co on W results in a strain and/or texture that reduces the interfacial DMI, and, to some extent, MCA at small $t_\mathrm{eff}$.
Magnetodipolar interlayer interaction effect on the magnetization dynamics of a trilayer square element with the Landau domain structure
我们提出了一个详细的数值模拟研究的影响所造成的三层磁性纳米元件的铁磁（FM）层之间的磁偶极相互作用的磁化动力学。作为示例，我们使用具有正方形横向形状的Co/Cu/Ni 80 Fe 20元件，其中FM层的磁化形成封闭的朗道状畴图案。首先，我们表明，当非磁性（NM）的间隔物的厚度是在技术相关的区域h ~ 10 nm，FM层中的90 o Neel畴壁之间的磁偶极相互作用定性地改变这些层的平衡磁化状态。在本文的主要部分，我们比较了单层Ni_（80）Fe_（20）（Py）元件和Co/Cu/Py三层元件中由亚纳秒场脉冲引起的磁化动力学。结果表明：（i）由于FM/NM/FM三层中朗道态的自发对称性破缺，三层磁畴和畴壁以不同的频率振荡，并具有不同的空间振荡模式：（ii）Co和Py中磁畴的不同振荡频率强烈抑制了三层磁畴的磁化振荡;（iii）磁化动力学定性地取决于Co和Py层中磁化状态的相对旋转方向以及Co微晶的磁晶各向异性类型。最后，我们讨论了我们的研究结果与实验观察的磁化动力学在磁性三层，使用特定元素的时间分辨X射线显微镜进行。
Spin-waves in the collinear antiferromagnetic phase of Mn$_\bf{5}$Si$_\bf{3}$
本文结合非弹性中子散射测量和密度泛函理论计算两种独立的方法，研究了Mn $_5$ Si $_3$高温共线反铁磁相（AFM 2）中的自旋波.我们得到了它的磁基态性质和电子结构。这项研究使我们能够确定主要的磁交换相互作用和磁晶各向异性的AFM 2相的Mn $_5$ Si $_3$。此外，自旋激发谱的演变的影响下，外部磁场垂直于各向异性易轴的影响进行了研究。低能磁振子模表现出不同的磁场依赖性，这是它们不同的岁差性质的直接结果。最后，还考虑了与Dzyaloshinskiii-Moriya相互作用相关的可能影响。
