Spin transport in insulators without exchange stiffness
Spin transport in insulators without exchange stiffness
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DOI：
10.1038/s41467-019-12749-7
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发表时间：
2019-10-18
影响因子：
16.6
通讯作者：
Saitoh, Eiji
中科院分区：
文献类型：
--
作者：
Oyanagi, Koichi;Takahashi, Saburo;Saitoh, Eiji
有效传输自旋电流的新材料的发现对于自旋电子学和材料科学具有重要意义。电绝缘体Gd_3Ga_5 O_（12）（GGG）是生长磁性薄膜的标准衬底，可以是自旋电流发生器，但从未被认为是自旋电流的上级导管。在这里，我们报告自旋电流传播在顺磁GGG超过几微米。令人惊讶的是，自旋输运持续到100 K >> T-g = 180 mK的温度，GGG的磁性玻璃状转变温度。在5 K和3.5T下，我们发现自旋扩散长度λ（GGG）= 1.8 ± 0.2 μ m，自旋电导率σ（GGG）=（7.3 ± 0.3）× 10（4）Sm-1，大于记录质量磁体Y_3Fe_5 O_（12）（YIG）的自旋电导率σ。我们的结论是，交换刚度是不需要有效的自旋输运，这挑战了传统的模型，并提供了新的材料设计策略的自旋电子器件。
The discovery of new materials that efficiently transmit spin currents has been important for spintronics and material science. The electric insulator Gd3Ga5O12 (GGG), a standard substrate for growing magnetic films, can be a spin current generator, but has never been considered as a superior conduit for spin currents. Here we report spin current propagation in paramagnetic GGG over several microns. Surprisingly, spin transport persists up to temperatures of 100 K >> T-g = 180 mK, the magnetic glass-like transition temperature of GGG. At 5 K and 3.5 T, we find a spin diffusion length lambda(GGG) = 1.8 +/- 0.2 mu m and a spin conductivity sigma(GGG) = (7.3 +/- 0.3) x 10(4) Sm-1 that is larger than that of the record quality magnet Y3Fe5O12 (YIG). We conclude that exchange stiffness is not required for efficient spin transport, which challenges conventional models and provides new material-design strategies for spintronic devices.