Identification of a disordered magnetic phase in pure nanocrystalline iron

A magnetically disordered state was experimentally identified in bulk nanoc rystalline iron at low temperatures. The structure and purity of as-milled samples (one milled in a helium atmosphere and the other in vacuum) were ch ecked by X-ray diffraction and transmission electron microscopy methods. Lo w-field and high-field hysteresis loops at different temperatures as well a s field-cooled and zero-field-cooled magnetization measurements at differen t external magnetic fields are presented. Frozen magnetic states were obser ved in both samples. It appears that ball-milled iron behaves much like a t wo component system with a ferromagnetic and a spin-glass-like phase.