Exchange bias and magnetization process of Co/CoO nanocomposite thin films
Yi, J. B.
Liu, Bing Hai
White, Timothy John
Date of Issue2004
School of Materials Science and Engineering
Co/CoO nanocomposite thin films have been deposited by RF sputtering with different oxygen partial pressures in the working atmosphere. It has been found that the magnetic properties (exchange bias (EB), coercivity and remanence) of the films are strongly dependent on the oxygen partial pressure. Film deposited with an O2 pressure of 0.75×10^−5 Torr shows a relatively high coercivity and high remanence ratio. Enhanced asymmetry of magnetization reversal appears in the film deposited with 1.5×10^−5 Torr O2 partial pressure. When the O2 partial pressure is increased to 3.0×10^−5 Torr, a strong reduction in EB and coercivity have been obtained. The investigation of the microstructure using high-resolution transmission electron microscope reveals that the change in EB, remanence and coercivity is probably related to the competition between dipolar interaction and exchange coupling. Magnetoresistance and extraordinary Hall effect (EHE) of the Co/CoO nanocomposite films is also investigated in dependence on oxygen partial pressure. The film deposited under 2.3×10^−5 Torr of oxygen exhibits strongly enhanced asymmetric magnetization reversal and unusually high EHE with a high coercivity.
Journal of magnetism and magnetic materials
© 2004 Elsevier B.V. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Magnetism and Magnetic Materials, Elsevier B.V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1016/j.jmmm.2004.07.044].