Metallic glass ultrathin films with hierarchical structure and their dynamic and thermodynamic behavior.

Metallic glass (MG) ultrathin films with hierarchical structure were in situ grown and characterized by scanning tunneling microscopy. A reversible dynamic behavior is observed at 77 K indicating a high mobility within the Fe85Sc15 MG ultrathin films. The complete scheme of the phase transition from amorphous solid to supercooled liquid and further to the crystalline phase is depicted. We find Fe85Sc15 MG ultrathin films with a reduction of the glass transition temperature of ∼290 K and an expanded temperature window of the supercooled liquid region of 180 K, which is almost 6 times larger than that of the conventional bulk MG with identical composition.