/NiFe heterostructures

As worldwide demand for computing grows exponentially and processors become increasingly powerful, the need for memory technologies that are energy efficient, non-volatile and capable of ultrafast read/write operations is urgent. One promising technique is the use of materials with spin-orbit coupling to control magnetic layers using spin-orbit torque. In this talk I will discuss our group’s ongoing work to leverage spin-momentum locking in topological insulators to manipulate magnets, as measured using Kerr Rotation and using both pulsed and DC current modalities. I will focus on recent results in which we have switched the in-plane moment of a NiFe layer in a Bi₂Se₃/NiFe structure in which the Bi₂Se₃ has been specially engineered to be bulk insulating, maximizing the spin-momentum locking in the charge current. We find that we are able to switch the NiFe layer using a current density in the Bi₂Se₃ more than an order of magnitude lower than required in more commonly used heavy metals. I will contextualize these results with transport and spin-torque ferromagnetic resonance measurements before closing with some discussion of future work.