垂直磁隧道结中自由层的铁磁共振线宽增强
Enhanced ferromagnetic resonance linewidth of the free layer in perpendicular magnetic tunnel junctions.
作者信息
Gopman D B, Dennis C L, McMichael R D, Hao X, Wang Z, Wang X, Gan H, Zhou Y, Zhang J, Huai Y
机构信息
Materials Science and Engineering Division, NIST, Gaithersburg, MD 20899, USA.
Center for Nanoscale Science and Technology, NIST, Gaithersburg, MD 20899, USA.
出版信息
AIP Adv. 2017 Mar;7(5). doi: 10.1063/1.4977969. Epub 2017 Mar 3.
We report the frequency dependence of the ferromagnetic resonance linewidth of the free layer in magnetic tunnel junctions with all perpendicular-to-the-plane magnetized layers. While the magnetic-field-swept linewidth nominally shows a linear growth with frequency in agreement with Gilbert damping, an additional frequency-dependent linewidth broadening occurs that shows a strong asymmetry between the absorption spectra for increasing- and decreasing external magnetic field. Inhomogeneous magnetic fields produced during reversal of the reference and pinned layer complex is demonstrated to be at the origin of the symmetry breaking and the linewidth enhancement. Consequentially, this linewidth enhancement provides indirect information on the magnetic coercivity of the reference and pinned layers. These results have important implications for the characterization of perpendicular magnetized magnetic random access memory bit cells.
我们报道了具有全垂直于平面磁化层的磁性隧道结中自由层铁磁共振线宽的频率依赖性。虽然磁场扫描线宽名义上与吉尔伯特阻尼一致，随频率呈线性增长，但会出现额外的频率依赖性线宽展宽，这在外部磁场增加和减少时的吸收光谱之间表现出强烈的不对称性。在参考层和钉扎层复合体反转过程中产生的不均匀磁场被证明是对称性破坏和线宽增强的根源。因此，这种线宽增强提供了关于参考层和钉扎层磁矫顽力的间接信息。这些结果对垂直磁化磁性随机存取存储器位单元的表征具有重要意义。
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