| Summary: | 碩士 === 國立成功大學 === 物理學系 === 104 === Spin pumping is a mechanism that generates spin currents from ferromagnetic metal (FM) and injects into normal metal (NM), while we can detect ISHE voltage signal in the NM layer. We choose Y3Fe5O12 (YIG) grown on Gd3Ga5O12 (GGG) as ferromagnetic metal insulator (FMI) layer, and Bismuth Selenide (Bi2Se3) as NM layer which transfers pure spin current into charge current. We changed the thickness of Bi2Se3 in this experiment, and choose the appropriate thickness to adulterate Antimony (Sb), while doping Sb is used as decreasing the carrier concentration and increasing the thin film resistance in Bi2Se3. We observed the changing of spin pumping voltage signal after doping Sb, and discussed the origin of changing in spin pumping signal.
In our experiment, we observed two results after doping Sb in Bi2Se3, for one thing, the spin pumping voltage has increased, and for another thing, the spin current conversion efficiency has decreased. This consequence might come from the changing of film resistance and Sb substituting in Bi site.
After all, we get high spin current conversion efficiency in Bi2Se3 system, and get high spin current detection efficiency in Sb-doped Bi2Se3 system. This experiment shows that topological insulators with strong spin-orbit coupling could be used in spintronic devices at room temperature.
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