论文标题
理解基于轨道和四杆矩的磁晶对
Understanding magnetocrystalline anisotropy based on orbital and quadrupole moments
论文作者
论文摘要
了解磁晶型各向异性（MCA）对于开发新型磁性材料至关重要。因此，必须阐明通过光谱测量值观察到的MCA与局部物理量之间的关系，例如轨道和四极矩。在这篇综述中，我们根据轨道和四极矩的MCA和带有过渡金属（TMS）的磁性材料的失真效应，分别与二阶扰动计算中的旋转式和自旋flip项有关。我们揭示了轨道矩稳定在较大的轨道矩的方向上的旋转力矩，而四极矩沿旋转密度分布的纵向方向稳定了旋转力矩。带有TMS及其界面的磁性材料的MCA可以从这两个贡献之间的竞争中确定。我们表明，带有拉伸四方失真的面部中心（FCC）Ni的垂直MCA来自轨道矩各向异性，而Mn-GA合金的垂直于四方扭曲的MCA来自旋转型合金的垂直。相反，在CO/PD（111）多层和Fe/Mgo（001）中，轨道矩各向异性和旋转密度的四极力矩在接口上有助于垂直MCA。了解基于轨道和四极力矩的磁性材料和接口的MCA对于设计新型磁性应用的MCA至关重要。
Understanding magnetocrystalline anisotropy (MCA) is fundamentally important for developing novel magnetic materials. Therefore, clarifying the relationship between MCA and local physical quantities observed by spectroscopic measurements, such as the orbital and quadrupole moments, is necessary. In this review, we discuss MCA and the distortion effects in magnetic materials with transition metals (TMs) based on the orbital and quadrupole moments, which are related to the spin-conserving and spin-flip terms in the second-order perturbation calculations, respectively. We revealed that orbital moment stabilized the spin moment in the direction of the larger orbital moment, while the quadrupole moment stabilized the spin moment along the longitudinal direction of the spin-density distribution. The MCA of the magnetic materials with TMs and their interfaces can be determined from the competition between these two contributions. We showed that the perpendicular MCA of the face-centered cubic (fcc) Ni with tensile tetragonal distortion arose from the orbital moment anisotropy, whereas that of Mn-Ga alloys originated from the quadrupole moment of spin density. In contrast, in the Co/Pd(111) multilayer and Fe/MgO(001), both the orbital moment anisotropy and quadrupole moment of spin density at the interfaces contributed to the perpendicular MCA. Understanding the MCA of magnetic materials and interfaces based on orbital and quadrupole moments is essential to design MCA of novel magnetic applications.
