, 61:76

The synthesis and magnetic properties of a nanostructured Ni-MgO system

  • J. Narayan
  • Sudhakar Nori
  • S. Ramachandran
  • J. T. Prater
Spintronic Materials and Devices Research Summary


We have investigated the magnetic properties of the Ni-MgO system with an Ni concentration of 0.5 at.%. In asgrown crystals, Ni ions occupy substitutional Mg sites. Under these conditions the Ni-MgO system behaves as a perfect paramagnet. By using a controlled annealing treatment in a reducing atmosphere, we were able to induce clustering and form pure Ni precipitates in the nanometer size range. The size distribution of precipitates or nanodots is varied by changing annealing time and temperature. Magnetic properties of specimens ranging from perfect paramagnetic to ferromagnetic characteristics have been studied systematically to establish structure-property correlations. The spontaneous magnetization data for the samples, where Ni was precipitated randomly in MgO host, fits well to Bloch’s T3/2-law and has been explained within the framework of spin wave theory predictions.


  1. 1.
    C.L. Chien, Annu. Rev. Mater. Sci., 25 (1995), p. 129.CrossRefGoogle Scholar
  2. 2.
    J. Narayan et al., Appl. Phys. Lett., 93 (2008), p. 082507.CrossRefADSGoogle Scholar
  3. 3.
    S. Ramachandran et al., Solid State Commun., 145 (2008), p. 18.CrossRefADSGoogle Scholar
  4. 4.
    S. Ramachandran et al., Appl. Phys. Lett., 87 (2005), p. 172502.CrossRefADSGoogle Scholar
  5. 5.
    A. Tiwari et al., Appl. Phys. Lett., 88 (2006), p. 142511.CrossRefADSGoogle Scholar
  6. 6.
    J. Narayan and Y. Chen, Phil. Mag., A, 49 (1984), p. 475.CrossRefGoogle Scholar
  7. 7.
    M.M. Abraham, C.T. Butler, and Y. Chen, J. Chem. Phys., 55 (1971), p. 3752.CrossRefADSGoogle Scholar
  8. 8.
    J. Narayan, Y. Chen, and R.M. Moon, Phys. Rev. Lett., 46 (1981), p. 1491.CrossRefADSGoogle Scholar
  9. 9.
    S. Ramachandran, J.T. Prater, and J. Narayan, Appl. Phys. Lett. 90 (2007), p. 132511.CrossRefADSGoogle Scholar
  10. 10.
    E.C. Stoner and E.P. Wohlfarth, Philos. Trans. R. Soc. London, Ser. A, 240 (1948), p. 599.MATHCrossRefADSGoogle Scholar
  11. 11.
    C. Kittel, Introduction Solid State Physics, 5th edition (New York: Wiley, 1976), p. 465.Google Scholar
  12. 12.
    R.H. Kodama, J. Magn. Magn. Mater., 200 (1999), p. 359.CrossRefADSGoogle Scholar
  13. 13.
    B.D. Cullity, Introduction to Magnetic Materials (Reading, MA: Addison-Wesley, 1972), pp. 117, 347 and 415.Google Scholar
  14. 14.
    G. Xiao and C.L. Chien, J. App. Phys., 61 (1987), p. 3308.CrossRefADSGoogle Scholar
  15. 15.
    S. Gangopadhyay et al., Phys. Rev. B, 45 (1992), p. 9778.CrossRefADSGoogle Scholar
  16. 16.
    G. Xiao and C.L. Chien, J. App. Phys., 63 (1988), p. 4252.CrossRefADSGoogle Scholar
  17. 17.
    E.F. Kneller and F.E. Luborsky, J. App. Phys., 34 (1963), p. 656.CrossRefADSGoogle Scholar
  18. 18.
    A.H. Morrish, The Physical Principles of Magnetism, ed. (New York: Wiley. 1965).Google Scholar
  19. 19.
    J.L. Gittleman, B. Abeles, and S. Bozowski, Phys. Rev. B, 9 (1974), p. 3891.CrossRefADSGoogle Scholar
  20. 20.
    H. Li et al., IEEE Tans. Magn., 28 (1992), p. 3177.CrossRefADSGoogle Scholar

Copyright information

© TMS 2009

Authors and Affiliations

  • J. Narayan
    • 1
  • Sudhakar Nori
    • 1
  • S. Ramachandran
    • 1
  • J. T. Prater
    • 1
    • 2
  1. 1.NSF Center for Advanced Materials and Smart Structures, Department of Materials Science and EngineeringNorth Carolina State UniversityRaleighUSA
  2. 2.Materials Science DivisionArmy Research OfficeDurhamUSA

Personalised recommendations