Tuning of magnetic and structural properties of Fe60Al40 thin films by ion irradiation

The effects of ion implantation on the structural and magnetic properties of Fe60Al40 films, possessing A2 and B2 structure respectively, have been investigated by means of X-ray diffraction and Vibrating sample magnetometry. The studies show that the magnetic properties of the 250 nm thick Fe60Al40 films, showing a phase transition from para- to ferromagnetic state, depend on the structural order only. The evolution of ferromagnetism comes along with an abrupt disappearance of the (100)-superlattice peak.
The irradiation of superparamagnetic B2 Fe60Al40 with H+, He+ or Ne+ ions with different fluences at low temperatures led to an increase of saturation magnetization (MS) going along with a lattice expansion induced by structural disorder. This effect didn’t appear for proton irradiation at elevated temperatures (250 ∘C) where the ordered B2 was retained. The low temperature hydrogen implantation of disordered A2 Fe60Al40 films on the other hand decreased, unlike helium or neon irradiation, the lattice parameter and MS indicating a little ordering.
This might offer the possibility of H+ irradiation induced ordering of A2 Fe60Al40 thin films well below the ordering temperature.