Natural ferromagnetic resonance damping optimisation in thin Fe–Co–Zr–N/Ti–Al–N films with in-plane uniaxial anisotropy
Natural ferromagnetic resonance damping optimisation in thin Fe–Co–Zr–N/Ti–Al–N films with in-plane uniaxial anisotropy
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DOI：
10.1088/1361-6463/aa8495
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
K. Seemann;S. Beirle;H. Leiste
中科院分区：
文献类型：
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作者：
K. Seemann;S. Beirle;H. Leiste
采用反应磁控溅射法制备了具有非铁磁Ti-Al-N籽晶层和/或覆盖层的多层结构的铁磁Fe 40 Co 37 Zr 11N 12薄膜，并在400 °C下在静磁场中退火1 h，以诱导面内单轴各向异性。本文的重点是针对高频的适用性，这是由各种阻尼机制的影响。这些阻尼机制被分为以阻尼参数αint为特征的本征部分和来自非均匀性、种子层或/和盖层处的双磁振子散射以及磁性电子与作为自旋阱的非铁磁盖层的电子的相互作用的非本征阻尼αext。实验共振线数据被映射到Landau-Lifschitz-吉尔伯特微分方程的有效阻尼参数αeff上，并且是αeff = αint + αext的简单求和。通过改变铁磁薄膜的厚度，研究表明，它是方便的细分为两个额外的参数，分别描述自旋阱功能和双磁振子过程的非本征阻尼。通过实验和理论的考虑，可以观察到对于100和200 nm之间的膜厚度的最小有效阻尼。它表明，阻尼参数可以与铁磁共振的频率相关的磁导率的虚部的半高宽，这使得各种阻尼参数归因于特定的线加宽的贡献。
Ferromagnetic Fe40Co37Zr11N12 films in a multilayer arrangement with non-ferromagnetic Ti–Al–N seed- or/and capping layers were fabricated by reactive magnetron sputtering and post-annealed at 400 °C for 1 h in a static magnetic field, in order to induce an in-plane uniaxial anisotropy. The focus of the paper aims at the high-frequency suitability which is influenced by various damping mechanisms. These damping mechanisms were class-divided into an intrinsic part characterised by the damping parameter αint and extrinsic damping αext which comes from two-magnon scattering at inhomogeneity, at seed layers or/and capping layers as well as the interaction of the magnetic electrons with the electrons of the non-ferromagnetic capping layers acting as a spin sink. The experimental resonance line data are mapped on the effective damping parameter αeff of the Landau–Lifschitz–Gilbert differential equation and is simply a summation of αeff = αint + αext. By the variation of the ferromagnetic film thickness investigations have shown that it is convenient to subdivide extrinsic damping into two additional parameters which separately describe spin sink features and the two-magnon processes. By means of the experimental and theoretical consideration a minimum of the effective damping for a film thickness between 100 and 200 nm could be observed. It is demonstrated that the damping parameters can be correlated with the full width at half maximum of the imaginary part of the frequency-dependent permeability at ferromagnetic resonance which enables the various damping parameters to be attributed to the particular line broadening contributions.