Formation of unusual intermetallic phases by vacuum PLD

Unusual phase formation in Fe–Cr alloys co-deposited by pulsed laser deposition (PLD) is reported. Contrary to expectations to obtain a continuous series of supersaturated body centered cubic (b.c.c.) solid solutions, the structure of alloys develops from a tetragonally distorted b.c.c. at low Cr-content to an ordered primitive orthorhombic crystal structure of the A15 type at nearly equiatomic composition. It seems to be the first observation of an ordering of restrictedly soluble components under the bombardment of hyperthermal species in PLD. The film formation in PLD can be described in the frames of subplantation model of Lifshitz et al. where the phase that forms is a product of kinetic factors like defect formation beneath the free surface and their disintegration rather than thermodynamic driving forces.