Scientists have shown for the first time how single atoms may be able to magnetically encode single bits of information.
Hard disks store data by magnetizing small domains of a disk's surface so that the magnetic axis points in one of two opposing directions. Each orientation is stable because the domain's energy is at a minimum. Such stability helps keep the magnetic axis from wandering, which would corrupt the data.
To fit more data onto a surface, engineers would like to shrink the domains, working toward the ultimate limit of single atoms. But reliable data storage would still require energy-minimizing orientations to prevent random flips.