The spin of an individual atom can remain stable for more than 10 minutes and is therefore suitable for storing data. https://www.mpg.de/7616090/atom-spin-data-storage
The spin of an individual holmium atom can remain stable for more than 10 minutes, as a team including researchers from the Max Planck Institute for Microstructure Physics and Karlsruhe Institute of Technology (KIT) have discovered. One individual atom can therefore be used to store one data bit.
holmium atoms by symmetry Nature, 14 November 2013 DOI Other Interesting Articles Para-particles