Irradiation induced modifications in microstructural and magnetic property of Fe 50Ni 50 (permalloy)/Si interfacial structure

Abstract

The interfacial structures of Fe50Ni50/Si have been prepared by electron beam evaporation of the alloy on silicon substrates. X-ray diffraction data confirm the formation of the alloy phase of Fe50Ni50 and intermixed silicide phases of Fe5Si3, Ni3Si2, Ni2Si and NiSi. The structures have also been irradiated from swift heavy ions to study the effect of irradiation induced interfacial intermixing. Magnetic force microscopy (MFM) and magnetisation characteristics have been used to characterise the magnetic behaviour of as-prepared and irradiated structures. It is observed from the MFM that the magnetic domains are of sub-micron scale and there is a significant magnetic signal from the surface of the structure which becomes stronger for the irradiated structures. The observed magnetisation (M-H) characteristics show the presence of in-plane and out-of-plane magnetic anisotropy in the structure which has been observed to be removed on the irradiation. The magnetisation characteristics has been understood as the magnetic behaviour of nano-magnetic grains of silicides (and of the alloy, Fe50Ni50) which are formed as a result of interfacial chemistry and modified by irradiation induced interfacial intermixing. The observed magnetic behaviour seems interesting and significant for many applications related to magnetics. © 2013 © 2013 Taylor & Francis.