SOT-MRAM (spin-orbit torque MRAM) has the potential to challenge STT-MRAM, as it is a 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.

Now researchers at 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 - which means it could be used to create SOT-devices.

Researchers from Imec fabricated spin-orbit torque MRAM (SOT-MRAM) devices on 300mm wafers using CMOS compatible processes. The researchers say that these devices offer unlimited endurance, fast switching speeds and low power consumption.

Imec says that SOT-MRAM can overcome the limitation of spin-transfer torque in MRAM memories, but up until now it was only demonstrated in a lab. The core of the SOT-MRAM is a magnetic tunnel junction in which a thin dielectric layer is sandwiched between a magnetic fixed layer and a magnetic free layer. SOT-MRAM devices feature switching of the free magnetic layer done by injecting an in-plane current in an adjacent SOT layer, unlike STT-MRAM where the current is injected perpendicularly into the magnetic tunnel junction and the read and write operation is performed through the same path.