Natterer and colleagues created the minuscule magnetic bits using atoms of holmium deposited on a surface of magnesium oxide. (sciencenews.org)
Both studies examine the magnetic behavior of a family of rare - earth materials known as spin ices — one group using holmium titanate and the other dysprosium titanate. (scientificamerican.com)
With the help of STM, they built and measured the isolated single atom bits using holmium atoms. (technowize.com)