Anisotropic Ferromagnetism in Substituted Zinc Oxide

M. Venkatesan, C. B. Fitzgerald, J. G. Lunney, and J. M. D. Coey
Phys. Rev. Lett. 93, 177206 – Published 22 October 2004

Abstract

Room-temperature ferromagnetism is observed in (110) oriented ZnO films made from targets containing 5 at. % of Sc, Ti, V, Fe, Co, or Ni, but not Cr, Mn, or Cu ions. There are large moments, 2.6μB and 0.5μB/dopant atom for Co- and Ti-containing oxides, respectively. There is also a moment of 0.3μB/Sc. Magnetization is very anisotropic, with variations of up to a factor of 3 depending on the orientation of the applied field relative to the substrate. Results are interpreted in terms of a spin-split donor impurity-band model, which can account for ferromagnetism in insulating or conducting high-k oxides with concentrations of magnetic ions that lie far below the percolation threshold. Magnetic moments are associated with two-electron defects in the films as well as unpaired electrons of the 3d ions.

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  • Received 12 June 2004

DOI:https://doi.org/10.1103/PhysRevLett.93.177206

©2004 American Physical Society

Authors & Affiliations

M. Venkatesan, C. B. Fitzgerald, J. G. Lunney, and J. M. D. Coey

  • Physics Department, Trinity College, Dublin 2, Ireland

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Issue

Vol. 93, Iss. 17 — 22 October 2004

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