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Structural, electronic, and magnetic properties of a ferromegnetic semiconductor: Co-doped TiO$_2$ rutile

W. T. Geng·K. S. Kim
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Abstract

Room-temperature ferromagnetism has been recently discovered in Co-doped TiO$_2$ rutile. Our $ab$ $initio$ density-functional theory investigations show that the substitutional Co ions incorporated into TiO$_2$ rutile tend to cluster and then the neighboring interstitial sites become energetically favorable for Co to reside. This suggests that a Co-doped rutile containing only substitutional Co is not an appropriate reference bulk system in derterming the local environment of Co in polycrystalline (Ti,Co)O$_2$ rutile. We also find that the interstitial Co is in the low spin state and destroys the spin-polarization of the surrounding substitutional Co, hence reduces the average magnetic moment of impurity atoms.

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W. T. Geng, K. S. Kim. 2003-06-15. Structural, electronic, and magnetic properties of a ferromegnetic semiconductor: Co-doped TiO$_2$ rutile. https://arxiv.org/abs/cond-mat/0306390

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