SYNTHESIS, CHARACTERIZATION, AND MAGNETIC-PROPERTIES OF FE3O4 THIN-FILMS PREPARED VIA A SOL-GEL METHOD

Different thickness Fe3O4 thin films, deposited on quartz substrates, have been directly synthesized via a sol-gel method. Homogeneous sols for preparing Fe3O4 thin films were obtained by interacting iron salts and polydentate ligands in ethanol. X-ray diffraction (XRD) and therm ogravimetric analysis (TGA) identified the Fe3O4 phase and showed that there was no organic residue left in the films. A SQUID magnetometer was used to measure the coercive force of Fe3O4 thin films. The obtain ed coercive force of 30 Oe, measured from the trilayer thin film (275- nm thickness), showed the particles in the films were nanophase Fe3O4. A dramatic increase of coercivity of Fe3O4 thin films from 30 to 625 Oe and a demagnetization behavior, as the film thickness decreased fro m 275 to 120 nm, were observed on these films. (C) 1997 Academic Press .