Abstract
Contrary to theoretical prediction that Cr-doped bulk ZnO is ferromagnetic, recent experiments on Cr-doped ZnO thin film reveal the coupling to be antiferromagnetic. Using first-principles calculations based on gradient corrected density functional theory, we show that a possible origin of this disagreement may be associated with the site preference of Cr. In bulk, when Cr substitutes Zn, bond contraction occurs and Cr atoms prefer to cluster around O atoms. The ferromagnetic coupling among Cr atoms is driven by Cr 3d and O 2p exchange interactions as in Cr2 O cluster. However, when Cr atoms replace Zn on the surface, due to the different bonding environment, bonds expand preventing Cr atoms from clustering around O atoms. Consequently, the coupling between Cr atoms becomes antiferromagnetic.
Original language | English |
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Article number | 162509 |
Pages (from-to) | 1-3 |
Number of pages | 3 |
Journal | Applied Physics Letters |
Volume | 87 |
Issue number | 16 |
DOIs | |
Publication status | Published - 2005 Oct 17 |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)