Researchers from the Tokyo Institute of Technology have developed a new thin film material made from bismuth-antimony (BiSb) that is a topological insulator that simultaneously achieves a colossal spin Hall effect and high electrical conductivity.
This material could be used as the basis of spin-orbit torque MRAM (SOT-MRAM). SOT-MRAM SOT-MRAM can overcome the limitation of spin-transfer torque in MRAM memories - and provide a much faster, denser and much more efficient memory technology. Up until now, though, no suitable material that features both high electrical conductivity and a high spin hall effect was developed.
SOT-MRAM was recently demonstrated at imec, based on heavy metals which feature a low spin hall effect.
The new thin film achieves a colossal spin Hall angle of approximately 52, conductivity of 2.5 x 105 and spin Hall conductivity of 1.3Ã107 at room temperature. To create the films, the researchers used molecular beam epitaxy (MBE). The key factor behind the large spin hall effect could be a particular surface orientation named BiSb(012.
The researchers are now looking to collaborate with the industry and develop, test and scale-up BiSb-based SOT-MRAM.