Japanese physicists found a way to create faster and more power efficient MRAM:
The research team at Tohoku University has utilized a property of magnetic domains in a new way. Domains are the pockets within MRAM cells that hold either a charge or a void. And, like tiny magnets, domains have both a north and south pole.
In the currently dominant spin-torque model for MRAM, the ability to read or store a binary 1 or 0 depends on flipping the orientation of the charge in the domain by passing a current through tiny electromagnets nearby. North up means one value, south up means another. To read the data a small current is passed through a lead.
A similar approach is used to read the state of the charge using this new method. However, the manner in which the charge is stored is where the power savings come in.