Laser induced spin injection to [GeTe/Sb2Te3] superlattice through a TbFeCo film

A [GeTe/Sb2Te3] superlattice is known as a topological insulator and it shows magnetic responses such as magneto-optical effect although it does not contain any magnetic element. We reported the superlattice has topologically protected spin diffusion length more than 100 μm at room temperature. In this paper, we show a laser induced spin injection to the superlattice using a TbFeCo film. We got spin injection signals between the TbFeCo and the Pt bars through the superlattice without electric current. The signals showed the maximum value of 0.06 μV around laser power of 1.0 mW which was focused to a spot diameter of 0.7 μm. The laser induced spin injection method will be one of the useful methods for future low-energy spintronics devices.