Ferromagnetic Gd-implanted ZnO single crystals


Ferromagnetic Gd-implanted ZnO single crystals

Zhou, S.; Potzger, K.; Eichhorn, F.; Helm, M.; Skorupa, W.; Mücklich, A.; Fassbender, J.; Herrmannsdörfer, T.; Bianchi, A.

In order to introduce ferromagnetic properties, ZnO single crystals have been implanted with Gd ions at 180 keV ion energy and two different fluences. Magnetization reversal hysteresis loops have been recorded using a superconducting quantum interference device. The virgin ZnO shows a pure diamagnetic behaviour. Besides the diamagnetic background, weak ferromagnetism has been observed for the as-implanted films. Post-implantation annealing greatly improved the magnetism. For a fluence of 5x10ˆ15 Gd/cm2, post implantation annealing at 820K in vacuum leads to an increase of the saturation moment up to 1.8 Bohr magneton per Gd at exactly 300 K thus excluding Gd, ZnGd or Gd2O3 secondary phases to be formed. The increase of the saturation moment can be explained along with changes in resistivity due to the annealing reported elsewhere. Moreover magnetic domains were observed up to 2 microns by atomic/magnetic force microscope, which again evidenced the formation of diluted magnetic semiconductor.
[1]K. Potzger et al, submitted to J. Appl. Phys. (2005).
[2]S. O. Kucheyev et al. J. Appl. Phys. 93, 2972 (2003).

  • Lecture (Conference)
    DPG Frühjahrstagung 2006, 27.-31.03.2006, Dresden, Germany

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