From IBM:
The ability to move single atoms, one of the smallest particles of any element in the universe, is crucial to IBM's research in the field of atomic-scale memory. In 2012, IBM scientists announced the creation of the world's smallest magnetic memory bit, made of just 12 atoms. This breakthrough could transform computing by providing the world with devices that have access to unprecedented levels of data storage.
Read more here:
http://www.research.ibm.com/articles/madewithatoms.shtml
