We report element specific structural and magnetic investigations on Zn1-xCoxO epitaxial films using synchrotron radiation. Co dopants exclusively occupy Zn sites as revealed by x-ray linear dichroism leading to a high degree of structural perfection. Comparative magnetic field dependent measurements by x-ray magnetic circular dichroism and conventional magnetometry consistently show purely paramagnetic behavior for isolated Co dopant atoms with a magnetic moment of 4.8µB. However, the total magnetization is reduced by ~30%, indicating that Co-O-Co pairs are antiferromagnetically coupled. We find no sign of intrinsic ferromagnetism in Co:ZnO films.
Revised: July 1, 2008 |
Published: April 18, 2008
Citation
Ney A., A. Ney, K. Ollefs, S. Ye, T. Kammermeier, V. Ney, and T.C. Kaspar, et al. 2008.Absence of Intrinsic Ferromagnetic Interactions of Isolated and Paired Co Dopant Atoms in Zn1-xCoxO with High Structural Perfection.Physical Review Letters 100, no. 15:Art. No. 157201.PNNL-SA-57805.doi:10.1103/PhysRevLett.100.157201