Proximity effect in superconductor/conical magnet/ferromagnet heterostructures
Proximity effect in superconductor/conical magnet/ferromagnet heterostructures
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DOI：
10.1088/1367-2630/16/5/055005
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发表时间：
2013-11
影响因子：
3.3
通讯作者：
D. Fritsch;J. Annett
中科院分区：
文献类型：
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作者：
D. Fritsch;J. Annett
在超导体与铁磁金属的界面处，自旋单线态库珀对能以振荡和衰减的自旋单线态库珀对密度穿透到异质结构的铁磁部分。然而，如果界面允许自旋混合效应，则可以产生等自旋自旋三重态库珀对，可以进一步穿透异质结构的铁磁性部分，称为远程接近效应。在这里，我们提出了基于微观Bogoliubov-de Gennes方程在清洁极限下结合紧密结合模型的自洽解的自旋混合结果。特别地，我们在模型异质结构中加入了一个锥形磁铁来产生自旋-三重态库珀对，并分析了锥形和铁磁层厚度对不等自旋和等自旋-三重态对相关关系的影响。结果表明，与实验观察一致，要产生足够数量的等自旋自旋三重态库珀对，需要最小厚度的锥形磁体，以允许远距离接近效应。
At the interface between a superconductor and a ferromagnetic metal spin-singlet Cooper pairs can penetrate into the ferromagnetic part of the heterostructure with an oscillating and decaying spin-singlet Cooper pair density. However, if the interface allows for a spin-mixing effect, equal-spin spin-triplet Cooper pairs can be generated that can penetrate much further into the ferromagnetic part of the heterostructure, known as the long-range proximity effect. Here, we present results of spin-mixing based on self-consistent solutions of the microscopic Bogoliubov–de Gennes equations in the clean limit incorporating a tight-binding model. In particular, we include a conical magnet into our model heterostructure to generate the spin-triplet Cooper pairs and analyse the influence of conical and ferromagnetic layer thickness on the unequal-spin and equal-spin spin-triplet pairing correlations. It will be shown that, in agreement with experimental observations, a minimum thickness of the conical magnet is necessary to generate a sufficient amount of equal-spin spin-triplet Cooper pairs allowing for the long-range proximity effect.