Thickness dependent microstructural and magnetic studies of iron embedded PVA nanocomposite films

This paper presents the structural and magnetic properties of polyvinyl alcohol/iron (PVA/Fe) nanocomposite films. Iron (Fe) films of different thicknesses were deposited on a PVA substrate using ion beam sputtering. The Fe nanoparticle layer thickness ranges from 3 to 50 nm on the PVA substrate. Grazing incidence x-ray diffraction has been carried out to study the structural behavior of the prepared films. An atomic force microscope records the indicated remarkable change in the roughness of the nanocomposite film as a result of initiation of vertical growth of sputtered Fe nanoparticles. Magneto-optic Kerr effect (MOKE) magnetometry and MOKE spectroscopy have been employed to evaluate the magnetic property and simultaneously study the real time growth of the magnetic domain structure for both 0(?) and 90(?) azimuthal angles. MOKE microscopic images indicated the magnetization reversal commensurate with the hysteresis loop of the nanocomposites. All the films show soft ferromagnetic behavior. Gradual development of the domain structure is observed in the MOKE micrograph with the increase in the thickness of Fe nanoparticle deposition. Ex situ magnetic force micrographs of the magnetic domain structures supported the observation of MOKE microscopic studies, which indicated switching of in-plane magnetization to out-of-plane magnetization near an Fe nanoparticle deposition thickness of 40 nm. The PVA matrix appears to be an effective material to support the growth of magnetic properties in the PVA/Fe nanocomposite system. The evolution of Fe nanostructures on PVA and the resulting magnetic behavior have been discussed.