Anisotropy constant and exchange coupling strength of perpendicularly magnetized CoFeB/Pd multilayers and exchange springs
Anisotropy constant and exchange coupling strength of perpendicularly magnetized CoFeB/Pd multilayers and exchange springs
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DOI：
10.1103/physrevb.95.144417
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发表时间：
2017-04-14
影响因子：
3.7
通讯作者：
Garcia, C.
中科院分区：
文献类型：
--
作者：
Franco, A. F.;Gonzalez-Fuentes, C.;Garcia, C.
利用描述多层结构铁磁共振行为的模型，通过与铁磁共振行为测量结果的比较，表征了具有垂直磁各向异性的[CoFeB/Pd]（n）多层膜和[CoFeB/Pd]（5）/（CoFeB或Co）交换弹簧结构中各组分的界面各向异性常数和层间交换耦合强度.我们发现，有效的垂直各向异性的多层，我们可以解释后，仅占不同的各向异性在底部重复垂直各向异性的多层的重复次数增加。类似地，我们的结构中的交换耦合的表征只有在考虑单个组件之后才可能，从而描绘了使用多层模型来正确描述多层结构的磁性行为和性质的重要性。我们发现当CoFeB的厚度从3埃增加到4埃时，非晶Pd/CoFeB/Pd结构的垂直各向异性常数从0.295增加到0.315 mJ/m（2）。此外，我们发现，在CoFeB/Pd（10 A度）/CoFeB结构的交换耦合从4.899下降到3.268 mJ/m（2）时，增加的CoFeB的厚度从3埃到4埃。最后，我们发现，在Co/Pd接口的各向异性的幅度是65%以上的CoFeB/Pd接口，并在CoFeB/Pd/Co接口的交换耦合降低约30%时，相比的CoFeB/Pd/CoFeB结构。
A model describing the ferromagnetic resonance of multilayer structures is used to characterize the interface anisotropy constant and interlayer exchange coupling strength associated to individual components of [CoFeB/Pd](n) multilayers with perpendicular magnetic anisotropy and [CoFeB/Pd](5)/(CoFeB or Co) exchange spring structures by comparing with ferromagnetic resonance behavior measurements. We find that the effective perpendicular anisotropy increases with the number of repetitions of the multilayer, which we could explain only after accounting for a different anisotropy at the bottom repetition of the multilayer with perpendicular anisotropy. Similarly, the characterization of the exchange coupling in our structures was only possible after accounting for individual components, thus portraying the importance of using a multilayer model to properly describe the magnetic behavior and properties of a multilayer structure. We find that the perpendicular anisotropy constant in amorphous Pd/CoFeB/Pd structures increases slightly from 0.295 to 0.315 mJ/m(2) when increasing the thickness of the CoFeB from 3 to 4 angstrom. Furthermore, we find that the exchange coupling in CoFeB/Pd(10 A degrees)/CoFeB structures decreases from 4.899 to 3.268 mJ/m(2) when increasing the thickness of the CoFeB from 3 to 4 angstrom. Finally, we find that the magnitude of the anisotropy at Co/Pd interfaces is 65% larger than at CoFeB/Pd interfaces, and the exchange coupling at CoFeB/Pd/Co interfaces decreases approximately 30% when compared to a CoFeB/Pd/CoFeB structure.