Micromagnetic modeling of terahertz oscillations in an antiferromagnetic material driven by the spin Hall effect
Micromagnetic modeling of terahertz oscillations in an antiferromagnetic material driven by the spin Hall effect
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DOI：
10.1103/physrevb.99.024405
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发表时间：
2019-01-07
影响因子：
3.7
通讯作者：
Finocchio, G.
中科院分区：
文献类型：
--
作者：
Puliafito, V;Khymyn, R.;Finocchio, G.
太赫兹（THz）光源的实现是其广泛应用的基础。在不同的方法，紧凑的太赫兹振荡器可以实现，利用反铁磁薄膜的动力学驱动的自旋霍尔效应。在这里，我们进行了系统的研究，这些太赫兹振荡器内的一个完整的微磁求解器的基础上的两个耦合的Landau-Lifshitz-Gilbert-Slonczewski方程的数值解，考虑薄膜。我们发现两种不同的动力学模式取决于Dzyaloshinskiii-Moriya相互作用的强度。在较低的磁化率下，激发出大幅度的进动，其中两个子晶格的磁化处于均匀状态并沿相同方向旋转。在足够大的矫顽力下，反铁磁体的基态变得不均匀，反铁磁体动力学的特征是超快畴壁运动。
The realization of terahertz (THz) sources is a fundamental aspect for a wide range of applications. Over different approaches, compact THz oscillators can be realized, taking advantage of dynamics in antiferromagnetic thin films driven by the spin Hall effect. Here we perform a systematic study of these THz oscillators within a full micromagnetic solver based on the numerical solution of two coupled Landau-Lifshitz-Gilbert-Slonczewski equations, considering ultrathin films. We find two different dynamical modes depending on the strength of the Dzyaloshinskii-Moriya interaction (DMI). At low DMI, a large-amplitude precession is excited, where both the magnetizations of the sublattices are in a uniform state and rotate in the same direction. At large enough DMI, the ground state of the antiferromagnet becomes nonuniform and the antiferromagnetic dynamics is characterized by ultrafast domain-wall motion.