The Notre Dame researchers took this idea a step further, by surrounding one nanomagnet with four others. Three of them act as “inputs” and determine the position of the central magnet. This configuration, in turn, determines the position of the “output” magnet. One of the inputs can then be used as a master control, establishing what sort of logic the magnets carry out. For instance, if two inputs are in an “up” position, the output is a magnet in the “down” position. This programmable logic gate can be used to perform all the operations a computer might need to do.
Gary Bernstein, electrical engineering professor at Notre Dame and one of the researchers on the project, says challenges remain before the particles can be used for large-scale computing. “We need to get a little bit better handle on the process, so the magnets are more uniform,” he says. “Also we need to have a good input and output structure” for feeding information into multiple logic gates and retrieving it after the logic is performed.
The first applications may not completely replace transistors, but instead augment them – Bernstein believes the particles can be layered on top of existing computer chip architectures and incorporated into current manufacturing processes.
For now, though, having a working device is a significant step forward. “You can always have a design or theory, but until you’ve actually committed and built it, there’s a thousand types of ‘gotchas,’” HP’s Williams says. “It’s a very clever idea, and the fact that they built it gives it that much extra bit of reality.”