SUPERPARAMAGNETISM IN A NANOCRYSTALLINE FE-BASED METALLIC-GLASS

It is shown that rapidly quenched Fe66Cr8CuNb3Si13B9 metallic glass, when annealed in a controlled way, shows superparamagnetic behavior at elevated temperatures. This property, as has been demonstrated, is due to the fine crystallites of the bcc-Fe(Si) solid solution created within the amorphous matrix by this annealing. Calculations performed show that the volumetric fraction of these particles is equal to 18%, and that their average dimension is as small as 10 nm. It is also shown that the single particle consists of approximately 10(4) atoms of iron. An analysis performed allows the conclusion that the particles are chemically stable (they do not increase their volumes at the time of measurements at elevated temperatures), and that there are no interactions between them.