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arXiv 1611.06554cond-mat.mes-hall
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双自旋过滤隧道结中自旋极化准粒子的控制

Spin-polarized quasiparticle control in a double spin-filter tunnel junction

P. K. Muduli

摘要:

在自旋过滤过程中,由于超导体与铁磁绝缘体之间的界面对断裂效应,可以很容易地产生自旋极化准粒子。夹在两个超导体之间的组合FI-N-FI可以用于通过它们在中间金属(N)层中的非平衡积累来创建和分析这样的自旋极化准粒子。本文报道了NbN-GdN_1-Ti-GdN_2-NbN双自旋过滤隧道结中的自旋极化准粒子调控。中间Ti层提供两个铁磁GdN之间的磁去耦和非平衡准粒子积累的地方。在不同的条件下沉积两个GdN(1,2)层以引入矫顽反差。在不同温度下测量了准粒子隧穿谱,以了解双自旋过滤结的隧穿机制。电导谱被发现是可比的不对称的SINI'S型隧道结。与平行态相比,反平行态的R-H环具有更高的电阻,表明了准粒子的自旋极化性质。在R-H环的滞后被发现消失的子间隙偏置电流。这种差异可以理解,通过考虑抑制层间耦合由于非平衡自旋极化准粒子在Ti层中的积累。

英文摘要:

Spin-polarized quasiparticles can be easily created during spin-filtering through a ferromagnetic insulator (FI) in contact with a superconductor due to pair breaking effects at the interface. A combination FI-N-FI sandwiched between two superconductors can be used to create and analyze such spin-polarized quasiparticles through their nonequilibrium accumulation in the middle metallic (N) layer. We report spin-polarized quasiparticle regulation in a double spin-filter tunnel junction in the configuration NbN-GdN1-Ti-GdN2-NbN. The middle Ti layer provides magnetic decoupling between two ferromagnetic GdN and a place for nonequilibrium quasiparticle accumulation. The two GdN(1,2) layers were deposited under different conditions to introduce coercive contrast. The quasiparticle tunneling spectra has been measured at different temperatures to understand the tunneling mechanism in these double spin-filter junctions. The conductance spectra were found to be comparable to an asymmetric SINI'S-type tunnel junction. A hysteretic R-H loop with higher resistance for the antiparallel configuration compared to parallel state was observed asserting the spin-polarized nature of quasiparticles. The hysteresis in the R-H loop was found to disappear for sub-gap bias current. This difference can be understood by considering suppression of the interlayer coupling due to nonequilibrium spin-polarized quasiparticle accumulation in the Ti layer.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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