Atomic electromagnets made from coils of individual gold atoms could prove valuable for nanocircuits and machines, a new study suggests.
Tomoya Ono and Kinkuji Hirose at Osaka University in southern Japan performed computer simulations to determine the electromagnetic properties of helical gold nanowires. These are rows of individual gold atoms twisted around a central axis – like a wire spring – which measure 0.6 nanometres wide by 5 nm long.
The calculations performed by Ono and Kinkuji were based on previous experiments and observations of helical gold nanowires. They found that the nanowires should generate a magnetic field as an electrical current passes through the atoms, just as larger conductive coils, known as solenoids, do.
These conductive coils are used in conventional electronic circuits or as electromechanical actuators – used to generate a force. For example, wrapping a coil around a ferromagnetic bar turns a regular solenoid into an actuator that exerts a force on the bar when the current is turned on.
So nano-solenoids could perhaps be used in super-efficient nanocircuits or as part of a nanoscopic machine. “It’s not always immediately clear what the applications may be,” says John Mintmire, nanomaterials expert at the Oklahoma State University, US. But he believes the wires could conceivably find use as simple motors for nanoscopic machinery.
Mintmire, however, notes that developing an atomic actuator could be fraught with difficulties, since surface friction on the nanoscale would make controlling such a tiny machine difficult.
“It’s not that it would be impossible,” he told New Scientist.” It’s just that the ground rules change on this scale.”
By Will Knight