Tiny magnets point to ultra low-power processors

Researchers at the Virginia Commonwealth University say that their work with layers of nanometre scale magnets could pave the way for processors so power efficient could draw the energy they need from their environment.

Such low power devices could be made possible by combining the emerging field of spintronics with new techniques involving nanometre scale magnets. They would have applications in medical implants - that could warn a patient of an oncoming epileptic seizure for example, in automated sensors, and potentially even in designing artificial synapses.

According to a report in PhysicsWorld.com, the scientists have shown that applying tiny voltages to layers of very small magnets induces a mechanical strain in a layer. This in turn affects the behaviour of the electron spins, lending the material to use in spintronic circuits.

From PhysicsWorld: The amount of voltage needed to generate the necessary stress is extremely small, at around 10 mV, explained [lead researcher] Kuntal Roy. Since the energy consumed by the magnet is proportional to the square of the voltage, the energy required to switch a bit is also very small.

"Conventional transistors switch in 1 nanosecond by dissipating one million kT of energy in a circuit," said Roy. "Our most recent results show that the multiferroic nanomagnets we used can switch in the same time while dissipating just 200 kT of energy in a circuit."

Some of the work is published in Applied Physics Letters, while some is still under review.