Brussels, 22 May 2003
A pan European team of physicists has measured the largest ever magnetic anisotropy energy (MAE). The finding will contribute to the design of new magnetic materials for information storage.
Researchers from Switzerland, Italy, France and Germany discovered that cobalt atoms on a platinum substrate can have a MAE of over nine milli-electron-volts.
Magnetic anisotropy is one of the most important properties of a magnetic material, and the MAE controls the positioning of atomic spins that cause magnetism in material. The greater the energy, the more stable the magnet.
The researchers used molecular beam epitaxy to place single cobalt atoms on a platinum substrate. They measured a MAE value around 200 times larger than that of cobalt atoms in a bulk crystal.
Over 100,000 atoms are currently needed to create a stable magnet for use in a hard disk. Using the new technique, however, the MAE of cobalt is so high that only a few hundred atoms would be needed, thus enabling a significant increase in storage density.