Hybrid spintronics and straintronics enable ultra-low-energy computing and signal processing

August 17, 2011

Virginia Commonwealth University researchers have combined spintronics and straintronics to create an integrated circuit design that runs on ambient energy from the environment — no batteries required.

The researchers used a special class of composite structure called multiferroics, which consist of a layer of piezoelectric material with intimate contact to a magnetostrictive nanomagnet (one that changes shape in response to strain). When a tiny voltage is applied across the structure, it generates strain in the piezoelectric layer, which is then transferred to the magnetostrictive layer. This strain rotates the direction of magnetism, achieving the flip of electrons either up or down.

With the proper choice of materials, the energy dissipated can be as low as 0.4 attojoules (a billionth of a billionth of a joule). The researchers said their proposed design would create an extremely low-power, yet high-density, non-volatile magnetic logic and memory system. Such processors would be well suited for implantable medical devices and could run on energy harvested from the patient’s body motion. They also could be incorporated into buoy-mounted computers that would harvest energy from sea waves, the researchers said.

Ref.: Kuntal Roy, Supriyo Bandyopadhyay, and Jayasimha Atulasimha, Hybrid spintronics and straintronics: A magnetic technology for ultra-low-energy computing signal processing, Applied Physics Letters, 2011; [DOI:10.1063/1.3624900]