有限温度下无序FeCo磁振子晶体的本征模
Eigenmodes of a disordered FeCo magnonic crystal at finite temperatures
摘要：
在这份报告中，我们提出了一个系统的研究磁振子模式的无序Fe $_{0.5}$ Co $_{0.5}$合金的基础上海森堡哈密顿使用两个互补的方法。为了考虑替代无序，一方面我们直接平均的横向磁化率在真实空间中不同的无序配置，另一方面，我们使用相干势近似（CPA）。虽然直接平均的方法在数值上是精确的，但它在计算上是昂贵的，并且受到可以在计算机上模拟的超原胞的最大尺寸的限制。相反，CPA不受这个缺点，并产生一个廉价的数值方案。因此，我们还比较了这两种方法的结果，并表明，CPA给出了非常好的结果，为大多数的磁性，包括磁振子能量和本征模的空间形状。然而，事实证明，虽然再现的一般趋势，CPA系统地低估了无序引起的阻尼的磁振子。这提供了证据表明，在这个系统中的杂质散射的物理是由非本地效应在CPA失踪。最后，我们研究了系统的实空间本征模，包括它们的空间形状，并在随机相位近似下分析了它们的温度依赖性。
英文摘要：
In this report we present a systematic study of the magnonic modes in the disordered Fe$_{0.5}$Co$_{0.5}$ alloy based on the Heisenberg Hamiltonian using two complementary approaches. In order to account for substitutional disorder, on the one hand we directly average the transverse magnetic susceptibility in real space over different disorder configurations and on the other hand we use the coherent potential approximation (CPA). While the method of direct averaging is numerically exact, it is computationally expensive and limited by the maximal size of the supercell which can be simulated on a computer. On the contrary the CPA does not suffer from this drawback and yields a cheap numerical scheme. Therefore, we additionally compare the results of these two approaches and show that the CPA gives very good results for most of the magnetic properties, including the magnon energies and the spatial shape of the eigenmodes. However, it turns out that while reproducing the general trend, the CPA systematically underestimates the disorder induced damping of the magnons. This provides evidence that the physics of impurity scattering in this system is governed by non-local effects missing in the CPA. Finally, we study the real space eigenmodes of the system, including their spatial shapes, and analyze their temperature dependence within the random phase approximation.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
