Magnetic properties of sputtered Fe1−xO and Fe+Fe3O4 thin films

Publisher Website
Google Scholar
Abstract
An attempt was made to increase saturation magnetization of Fe3O4 films by incorporating α-Fe phase through the decomposition of as-deposited Fe1−xO films, which were dc-sputtered onto Si(100) substrate by controlling the oxygen flow rates to a thickness of 70–400 nm. The as-prepared Fe1−xO films, being ferrimagnetic, show a thickness dependent microstructure and properties. The formation region of the single phase Fe1−xO was worked out as functions of oxygen flow rate and thickness. After vacuum-annealing, the Fe1−xO phase decomposed to Fe+Fe3O4 phases leading to an increase in coercivity from 15 Oe to 520–990 Oe, and an increase in saturation magnetization from 100 to 290–410 emu/cm3 depending on film thickness. The nanostructure of as-prepared and annealed films were examined by a high resolution transmission electron microscope, the former does not show well defined grain boundaries, while the later has well defined grains, 20–50 nm in size.