Electric field modulation of magnetism in ferrimagnetic Heusler heterostructures
Electric field modulation of magnetism in ferrimagnetic Heusler heterostructures
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DOI：
10.1103/physrevb.101.134419
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发表时间：
2020-03
期刊：
影响因子：
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通讯作者：
Qilong Sun;Sohee Kwon;M. Stamenova;S. Sanvito;N. Kioussis
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文献类型：
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作者：
Qilong Sun;Sohee Kwon;M. Stamenova;S. Sanvito;N. Kioussis
迄今为止，磁阻随机存取存储器（RAM）和磁电RAM（梅拉姆）器件的实现主要依赖于基于铁磁材料（FeCoB/MgO）的磁性隧道结。另一方面，Heusler家族的金属间化合物被认为是非常有前途的自旋电子应用。尽管如此，基于Heusler的磁性隧道结叠层中的电压控制磁各向异性（VCMA）仍然没有被探索。本文以亚铁磁Heusler ${\mathrm{Mn}}_{3}\mathrm{Ga}$为原型系统，报道了$\mathrm{Ir}/{\mathrm{Mn}}_{3}\mathrm{Ga}$/MgO异质结构中磁场调制的从头计算结果.与一个和三个单层Ir帽和Mn-Mn终止的三层结构表现出大的垂直磁各向异性与Mn-Ga终止，产生面内磁化取向。我们预测巨VCMA系数的大小和符号取决于界面终止和Ir帽厚度。潜在的原子机制在于电场诱导的自旋极化的$\mathrm{Ir}/d$轨道的自旋轨道耦合能量的移动具有不同的轨道角动量对称性。我们的论文为利用亚铁磁性Heusler化合物的独特磁性为下一代梅拉姆器件铺平了道路。
To date the realization of magnetoresistive random access memory (RAM) and magnetoelectric RAM (MeRAM) devices relies primarily on ultrathin ferromagnetic-based (FeCoB/MgO) magnetic tunnel junctions. On the other hand, the Heusler family of intermetallics is considered very promising for spintronic applications. Nevertheless, the voltage controlled magnetic anisotropy (VCMA) in ultrathin Heusler-based magnetic-tunnel junction stacks remains unexplored. Here, using the ferrimagnetic Heusler ${\mathrm{Mn}}_{3}\mathrm{Ga}$ as a prototype system, we report ab initio calculations of the electric field modulation of magnetism in the $\mathrm{Ir}/{\mathrm{Mn}}_{3}\mathrm{Ga}$/MgO heterostructure. The trilayer structures with one and three monolayer Ir caps and Mn-Mn termination exhibit large perpendicular magnetic anisotropy in contrast to those with Mn-Ga termination which yield in-plane magnetization orientation. We predict giant VCMA coefficients the magnitude and sign of which depend on both the interface termination and the Ir cap thickness. The underlying atomistic mechanism lies on the electric-field-induced shifts of the spin-orbit coupling energies of the spin-polarized $\mathrm{Ir}/d$ orbitals with different orbital angular momentum symmetries. Our paper paves the way for exploiting the unique magnetic properties of ferrimagnetic Heusler compounds for next generation MeRAM devices.