Radical chemistries have attracted burgeoning attention due to their intriguing technological applications in organic electronics, optoelectronics, and magneto-responsive systems. However, the potential of these magnetically active glassy polymers to transport spin-selective currents has not been demonstrated. Here, the spin-transport characteristics of the radical polymer poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (PTEO) allow for sustained spin-selective currents when incorporated into typical device geometries with magnetically polarized electrodes. Annealing thin films of PTEO above its glass transition temperature results in a giant magnetoresistance effect (i.e., an MR of ≈80%) at 4 K. Additionally, ferromagnetic resonance spin-pumping results in a relatively large effective spin-mixing conductance of 1.18 × 10¹⁹ m⁻² at the NiFe/PTEO interface. Due to the large spin-density and radical-radical exchange interactions, there is effective propagation of pure spin currents through PTEO in the NiFe/PTEO/Pd multilayer devices. This results in the transport of spin current over long distances with a spin diffusion length of 90.4 nm. The spin diffusion length and spin mixing conductance values surpass those reported in inorganic and metallic systems and are comparable to conventional doped conjugated polymers. This is the first example of spin transport in a nonconjugated radical polymer, and these findings underscore the promising spin-transporting potential of radical polymers.

中文翻译：

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非共轭自由基聚合物玻璃中的 Spintronic Pathways


自由基化学因其在有机电子学、光电子学和磁响应系统中的有趣技术应用而引起了人们的广泛关注。然而，这些磁性活性玻璃状聚合物传输自旋选择性电流的潜力尚未得到证明。在这里，自由基聚合物聚（4-缩水甘油氧基-2,2,6,6-四甲基哌啶-1-氧基）（PTEO）的自旋传输特性允许在掺入具有磁极化电极的典型器件几何形状时产生持续的自旋选择性电流。将 PTEO 薄膜退火至高于其玻璃化转变温度时，在 4 K 时会产生巨大的磁阻效应（即 ≈80% 的 MR）。此外，铁磁共振自旋泵浦在 NiFe/PTEO 界面处产生 1.18 × 10^{19 m-2} 的相对较大的有效自旋混合电导。由于大自旋密度和自由基-自由基交换相互作用，纯自旋电流在 NiFe/PTEO/Pd 多层器件中通过 PTEO 有效传播。这导致自旋电流长距离传输，自旋扩散长度为 90.4 nm。自旋扩散长度和自旋混合电导值超过了无机和金属体系中报道的值，与传统的掺杂共轭聚合物相当。这是非共轭自由基聚合物中自旋转运的第一个例子，这些发现强调了自由基聚合物有前途的自旋转运潜力。