Ferromagnetic resonance and voltage-induced transport in normal metal-ferromagnet-superconductor trilayers
Ferromagnetic resonance and voltage-induced transport in normal metal-ferromagnet-superconductor trilayers
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DOI：
10.1103/physrevb.84.104420
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发表时间：
2011-04
影响因子：
3.7
通讯作者：
H. J. Skadsem;A. Brataas;J. Martinek;Y. Tserkovnyak
中科院分区：
文献类型：
--
作者：
H. J. Skadsem;A. Brataas;J. Martinek;Y. Tserkovnyak
研究了在偏置电压和/或磁化进动诱导下正常金属-铁磁-超导体三层薄膜的亚隙自旋和电荷输运。根据时间相关散射理论讨论了输运性质。我们假设超导间隙在费米能量和铁磁交换分裂设定的能量尺度上很小，并计算了在有限外加电压存在下，非平衡电荷和自旋电流对进动频率的一阶响应。我们发现电压诱导的瞬时电荷电流和纵向自旋电流不受进动磁化的影响，而泵浦的横向自旋电流由自旋相关电导和电子-空穴散射矩阵的细节决定。对于铁磁体长度大于横向自旋相干长度的结构，导出了横向自旋电流的简化表达式。
We study the subgap spin and charge transport in normal metal-ferromagnet-superconductor trilayers induced by bias voltage and/or magnetization precession. Transport properties are discussed in terms of time-dependent scattering theory. We assume the superconducting gap is small on the energy scales set by the Fermi energy and the ferromagnetic exchange splitting, and compute the non-equilibrium charge and spin current response to first order in precession frequency, in the presence of a finite applied voltage. We find that the voltage-induced instantaneous charge current and longitudinal spin current are unaffected by the precessing magnetization, while the pumped transverse spin current is determined by spin-dependent conductances and details of the electron-hole scattering matrix. A simplified expression for the transverse spin current is derived for structures where the ferromagnet is longer than the transverse spin coherence length.