Department of Mechanical Engineering and Science, Kyoto University, Yoshida-hommachi, Sakyo-ku, Kyoto 606-8501, Japan.
J Phys Condens Matter. 2012 Mar 7;24(9):095303. doi: 10.1088/0953-8984/24/9/095303. Epub 2012 Feb 9.
We investigated a nanometer-sharp magnetic domain wall (DW) structure in a free-standing Fe(110) monolayer and studied the crucial role of in-plane strain using fully unconstrained noncollinear ab initio spin-density-functional theory calculations within the generalized gradient approximation. The DW width is calculated to be 0.86 nm. A precise vector-field description of the magnetization density revealed that a noncollinear character in the DW was spatially confined between atoms, whereas a collinear and high magnetization density was localized around each atom. In the rapid rotation of magnetic moments in the DW, we found an electron rearrangement from the d(zx) and d(x(2)-y(2)) states to the d(xy), d(yz) and d(z(2)) states due to a shift of band structures. Applied tensile and compressive in-plane strains both bring about narrower DWs in the monolayer except when the strain is small. The strain dependence of the DW width is discussed in terms of both exchange interaction and magnetocrystalline anisotropy.
我们研究了自由-standing Fe(110) 单层中的纳米级尖锐磁畴壁 (DW) 结构，并使用完全无约束的非共线 ab initio 自旋密度泛函理论计算，在广义梯度近似下，研究了面内应变的关键作用。DW 的宽度计算为 0.86nm。对磁化密度的精确矢量场描述表明，DW 中的非共线特征在原子之间空间受限，而共线且高磁化密度则局部化在每个原子周围。在 DW 中磁矩的快速旋转中，我们发现由于能带结构的位移，电子从 d(zx) 和 d(x(2)-y(2)) 态重新排列到 d(xy)、d(yz) 和 d(z(2)) 态。施加的拉伸和压缩面内应变都会导致单层 DW 变窄，除了应变较小时。DW 宽度的应变依赖性从交换相互作用和磁晶各向异性两个方面进行了讨论。
