Origin of room-temperature ferromagnetism in cobalt-doped ZnO
Thin films of ZnO doped with cobalt have been grown by the pulsed laser deposition (PLD) technique in different temperatures ranging from 500°C to 650°C. The films grown on sapphire c-plane single crystal were found to be highly epitaxial. Magnetic properties of these films were studied, and the films exhibited ferromagnetic characteristics at room temperature. Detailed structural and microstructural characterization was performed to correlate the fate of the magnetic impurities, i.e., cobalt, and the cause of magnetic properties. It is established from this work that the magnetic properties of these films are inherent to the system, and any presence of second phase/nanoclusters/precipitates are ruled out as the cause of magnetic properties. The techniques used to establish these were conventional and high-resolution transmission electron microscopy (HRTEM) along with electron-energy loss spectroscopy (EELS) and scanning transmission electron microscopy-atomic number (STEM-Z) contrast studies.
Key wordsZnO Co ferromagnetism pulsed laser deposition
Unable to display preview. Download preview PDF.
- 6.K. Sato and H.K. Yoshida, Mater. Res. Soc. Symp. Proc. 666, F4.6.1 (2001).Google Scholar
- 7.N. Theodoropoulou, A.F. Hebard, M.E. Overberg, C.R. Abernathy, S.J. Pearton, S.N.G. Chu, and R.G. Wilson, Res. Soc. Symp. Proc. 674, T6.8.1 (2001).Google Scholar
- 12.D.B. Chrisey and G.H. Hubler, Pulsed Laser Deposition of Thin Films (New York: John Wiley and Sons Inc., 1994).Google Scholar
- 14.P. Hirsch, A. Howie, R.B. Nicholoson, D.W. Pashley, and M.J. Whelan, Electron Microscopy of Thin Crystals, 2nd ed. (Huntington, NY: Robert E. Kreiger Pub. Co., 1977), p. 314.Google Scholar
- 19.T. Dietl and H. Ohno, Mater. Res. Soc. Bull. 28, 714 (2003).Google Scholar