Spin transport characteristics modulated by GeBi interlayer in Y3Fe5O12/GeBi/Pt heterostructures

For the past few years, germanium-based semiconductor spintronics has attracted considerable interest due to its potential for integration into mainstream semiconductor technology. The main challenges in the development of modern semiconductor spintronics are the generation, detection, and manipulation of spin currents. Here, the transport characteristics of a spin current generated by spin pumping through a GeBi semiconductor barrier in Y 3 Fe 5 O 12 /GeBi/Pt heterostructures were investigated systematically. The effective spin-mixing conductance and inverse spin Hall voltage to quantitatively describe the spin transport characteristics were extracted. The spin-injection efficiency in the Y 3 Fe 5 O 12 /GeBi/Pt heterostructures is comparable to that of the Y 3 Fe 5 O 12 /Pt bilayer, and the inverse spin Hall voltage exponential decays with the increase in the barrier thickness. Furthermore, the band gap of the GeBi layer was tuned by changing the Bi content. The spin-injection efficiency at the YIG/semiconductor interface and the spin transportation within the semiconductor barrier are related to the band gap of the GeBi layer. Our results may be used as guidelines for the fabrication of efficient spin transmission structures and may lead to further studies on the impacts of different kinds of barrier materials.