DNA data storage sounds like the stuff of science fiction, yet other technologies look even farther out. Spintronics data storage offers greater storage density and stability than magnetic storage, if engineers can get it to work. It depends on the quantum property of an electron called “spin,” which is a measure of angular momentum but doesn’t exactly mean the electron is spinning like an orbiting planet. Analogies of quantum properties to the macroscopic world don’t work very well.
It turns out there are more kinds of magnetism than the ferromagnetism we’re familiar with. Spintronics uses antiferromagnetism. With ferromagnetic materials, ions all line up their individual magnetic fields in the same direction, so that the material overall has a noticeable magnetic field. In antiferromagnetic materials, they line up in “antiparallel” formation, head to head and tail to tail, so that the fields cancel out and there’s no magnetic field on a large scale. With materials of this kind, it’s feasible (for cutting-edge values of “feasible”) to manipulate the spin of the electrons of individual atoms (or perhaps pairs of atoms is more exact), flipping them magnetically.