Phonon, electron, and magnon excitations in antiferromagnetic L10 -type MnPt
Phonon, electron, and magnon excitations in antiferromagnetic L10 -type MnPt
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DOI：
10.1103/physrevb.107.064412
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发表时间：
2021-12
影响因子：
3.7
通讯作者：
Kisung Kang;D. Cahill;A. Schleife
中科院分区：
文献类型：
--
作者：
Kisung Kang;D. Cahill;A. Schleife
反铁磁L1 $0 $型MnPt是一种具有相对简单的晶体结构和磁结构的材料，由于其高的N 'e el温度和广泛的用作磁性器件的钉扎层而引起人们的兴趣。虽然它在实验上得到了很好的表征，但理论上的理解却少得多，部分原因是由于控制反铁磁金属中磁有序的小的潜在能量尺度所决定的具有挑战性的精度要求。在这项工作中，我们使用密度泛函理论，Korringa-Kohn-Rostoker形式主义，和海森堡模型建立一个全面的理论描述的反铁磁L1$_{0}$型MnPt，沿着的精度限制，通过彻底比较现有的文献数据。我们的模拟结果表明，磁偶极相互作用对磁晶各向异性能的贡献K_{1}$= 1.07$\times10 ^{6}$\，J/m$^3$在量级上与自旋-轨道的贡献相当.使用我们的结果为5.25\times10 ^{-4}$，最低的磁振子频率约为2.02\，THz的预测，确认太赫兹自旋动力学在这种材料。从电子、声子和磁振子色散的数据中，我们计算了它们对总热容的贡献，并表明在2K或以上的主要项来自声子。从Landau-Lifshitz-吉尔伯特方程出发，计算出Nel温度为990--1070 K.最后，我们量化的大小的磁光克尔效应所产生的施加外部磁场。我们的研究结果提供了深入了解的基础物理，这是至关重要的深刻理解的基本限制的时间尺度的自旋动力学，磁有序的稳定性，以及磁光探测集体自旋运动的可能性。
Antiferromagnetic L1$_{0}$-type MnPt is a material with relatively simple crystal and magnetic structure, recently attracting interest due to its high N{\'{e}}el temperature and wide usage as a pinning layer in magnetic devices. While it is experimentally well characterized, the theoretical understanding is much less developed, in part due to the challenging accuracy requirements dictated by the small underlying energy scales that govern magnetic ordering in antiferromagnetic metals. In this work, we use density functional theory, the Korringa-Kohn-Rostoker formalism, and a Heisenberg model to establish a comprehensive theoretical description of antiferromagnetic L1$_{0}$-type MnPt, along with accuracy limits, by thoroughly comparing to available literature data. Our simulations show that the contribution of the magnetic dipole interaction to the magnetocrystalline anisotropy energy of $K_{1}$=1.07$\times 10^{6}$\,J/m$^3$ is comparable in magnitude to the spin-orbit contribution. Using our result for the magnetic susceptibility of $5.25\times10^{-4}$, a lowest magnon frequency of about 2.02\,THz is predicted, confirming THz spin dynamics in this material. From our data for electron, phonon, and magnon dispersion we compute the individual contributions to the total heat capacity and show that the dominant term at or above 2\,K arises from phonons. From the Landau-Lifshitz-Gilbert equation, we compute a N\'{e}el temperature of 990--1070 K. Finally, we quantify the magnitude of the magneto-optical Kerr effect generated by applying an external magnetic field. Our results provide insight into the underlying physics, which is critical for a deep understanding of fundamental limits of the time scale of spin dynamics, stability of the magnetic ordering, and the possibility of magneto-optical detection of collective spin motion.