According to the team, a single atom or small molecule could be used to store data. This is theoretically possible because certain atoms can be magnetised in only one of two possible directions: ‘spin up’ or ‘spin down’. Information could then be stored and read by the sequence of the molecules' magnetisation directions.
To achieve this, the team developed a molecule with a dysprosium atom at its centre. The atom is surrounded by a molecular scaffold that serves as a vehicle.
The scientists then deposited the molecules on the surface of silica nanoparticles, fusing them by annealing at 400°C. The molecular structure used as a vehicle disintegrated in the process, yielding nanoparticles with dysprosium atoms well-dispersed at their surface. The scientists showed that these atoms can be magnetised and maintain their magnetic information.
"Nanoparticles bonded with dysprosium can be made in any chemical laboratory. No cleanroom and complex equipment are required," says doctoral student Florian Allouche. In addition, the magnetisable nanoparticles can be stored at room temperature and re-used.
The magnetisation process, however, currently only works at -270°C, and the magnetisation maintained for up to 1.5min. The scientists are therefore looking for methods that will allow the magnetisation to be stabilised at higher temperatures and for longer periods of time. They are also looking for ways to fuse atoms to a flat surface instead of to nanoparticles.