Tunneling spin polarization measurements from ferromagnet/MgO tunnel junctions using NbN superconductor
Tunneling spin polarization measurements from ferromagnet/MgO tunnel junctions using NbN superconductor
复制标题
使用 NbN 超导体对铁磁体/MgO 隧道结进行隧道自旋极化测量
DOI：
10.1063/1.2200473
复制
发表时间：
2006
影响因子：
4
通讯作者：
S. Parkin
中科院分区：
文献类型：
--
作者：
Hyunsoo Yang;See;C. Kaiser;S. Parkin
超导铝电极通常用于使用超导隧道光谱测量隧道电流的自旋极化，但温度远低于 1K。使用 NbN 超导电极，我们证明可以在高温 (~1.2K) 下进行测量，从而消除了对 He3 稀释制冷机的需要。使用 NbN 准粒子态密度的强耦合理论，可以通过拟合从实验数据中提取隧道自旋极化值。人们还探索了 Nb 和 Ta 电极，但 NbN 因其自旋轨道散射率低得多，但超导转变温度更高，是最有吸引力的。
Superconducting aluminum electrodes have typically been used to measure the spin polarization of tunneling current using superconducting tunneling spectroscopy but at temperatures well below 1K. Using NbN superconducting electrodes we show that measurements at elevated temperatures (∼1.2K) are possible, thereby eliminating the need for the He3 dilution refrigerators. Tunneling spin polarization values can be extracted from the experimental data by fits using a strong coupling theory of the quasiparticle density of states of NbN. Nb and Ta electrodes were also explored but NbN, with its much lower spin-orbit scattering rate, yet higher superconducting transition temperature, is the most attractive.