Researchers from the Trinity College in Dublin developed a new device using a stack of five metal layers (including a platinum layer and an iron-based layer) that can be used to control the spin of electrons - using "spin–orbit torque", or SOT, an alternative to spin-transfer torque (STT) - but without an external field.
The basic idea is that when a current is run through the platinum, the electrons split into two groups by their spin (that's the SOT effect). Electrons are inserted into the iron-based "storage layer" and the spin of those electrons can be changed. The rest of the layers act like a thin-film magnet which helps determine the spin of the electrons.
The researchers demonstrated a basic device, and are now working to develop a full-memory cell.