Ion-beam mixing in an immiscible Fe/Ag multilayer film

Abstract

Ion-beam mixing of the thermally immiscible Fe/Ag system is studied by 90 keV Ar ϩ -ion irradiation of Fe/Ag multilayer at 325 K and the evolution of microstructure is studied by x-ray diffraction ͑XRD͒, x-ray reflectivity, and transmission electron microscopy ͑TEM͒. XRD measurements did not show any evidence of a additional phase formation or increase in solubility due to mixing of Fe in Ag. X-ray reflectivity analysis shows an initial sharpening at the interface for a fluence of 1ϫ10 16 ions/cm 2 and the destruction of multilayer periodicity is observed for higher fluences. The microstructural studies by TEM show a reduction in Ag particle size with fluence. The size of Ag nanoclusters was optimum at a fluence of 7ϫ10 16 ions/cm 2 and was found to be in the range of 10-20 nm. The particle density decreases at low fluence and on further irradiation, the particle density increases at higher ion fluences. This indicates the nucleation of Ag particles presumably due to long-range transport of Ag atoms. These Ag atom clusters give rise to a granular microstructure.

Ion beam induced surface and interface engineering

“…Thermal annealing on an irradiated multilayer results in sharp recovery of the reduced GMR, and can be associated with a backdiffusion process in metastably intermixed regions. In another work Ar ion irradiation on Fe/Ag multilayers at room temperature did not show any evidence of phase formation or an increase in solubility [462]. At low fluences, demixing or a chemically driven relaxation mechanism led to sharpening of the interface and, upon further irradiation, led to the destruction of multilayer periodicity observed at higher fluences.…”

Study of focused-ion-beam–induced structural and compositional modifications in nanoscale bilayer systems by combined grazing incidence x ray reflectivity and fluorescence

“…[37][38][39] Energy transfer from the incident ions can cause atomic displacements of target atoms, leading to intermixing across the interface. The re-arrangement of intermixed atoms initially located around the interfaces may induce alloy formation, 23,28,36,40,41 changes in grain size, 42 and lattice expansion due to local stress relaxation. Amorphisation, sputtering, and total destruction of the crystalline phase ultimately occur at higher doses.…”

Long-range ferromagnetic ordering at room temperature in Co+implanted TiO2nanorods

“…However, the precipitates apparently dissolve with higher irradiation fluence for the 9 at.% Co:TiO 2 NRs. Cluster dissolution with increasing fluence is possible in a miscible system with negative heat of mixing (−0.49 eV/atom for Co-Ti system [13]) and seems to originate from long-range diffusion of the clustered Co atoms in the case of irradiation at elevated temperature with increasing fluence [14]. The non-equilibrium segregation and doping phenomena happen during the radiation enhanced diffusion (RED) process of the ion implantation technique.…”