Effect of silver addition on structural, electrical and magnetic properties of Fe3O4 thin films prepared by pulsed laser deposition

The structural, electrical, and magnetic properties of Agx-(Fe3O4)1−x (x = 0, 0.02, 0.10) composite films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), resistivity as well as magnetization measurements. The samples used in the present work were prepared by the pulsed laser deposition (PLD) technique on a single crystal Si (111) substrate. XRD spectra reveal that Ag added samples show polycrystalline growth on the Si substrate in distinction to oriented growth of Fe3O4 on a similar substrate. XRD and XPS data confirm that silver is present in metallic form. Temperature dependent resistivity data corresponding to all the three samples show a characteristic Verway transition (Tv) around 121 K. However, the resistivity pattern of the Ag added sample with x = 0.10 shows the tunneling behavior below Tv, which is attributed to the accumulation of silver clusters across the boundary of Fe3O4 grains. Both Ag added (x = 0.02, 0.10) Fe3O4 films show positive magnetoresistance which is in contrast to negative magnetoresistance observed in pure Fe3O4 at room temperature. Magnetization measurements reveal that Ag granules reduce the saturation magnetization of Fe3O4.