Chemical Manipulation of High-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>T</mml:mi><mml:mi mathvariant="normal">C</mml:mi></mml:msub></mml:math>Ferromagnetism in ZnO Diluted Magnetic Semiconductors

We report the use of targeted p- and n-type chemical perturbations to manipulate high-T(C) ferromagnetism in Mn(2+):ZnO and Co(2+):ZnO in predictable and reproducible ways. We demonstrate a clear correlation between nitrogen and high-T(C) ferromagnetism for Mn(2+):ZnO and an inverse correlation for Co(2+):ZnO, both as predicted by recent theoretical models. These chemical perturbations reveal rich possibilities for exerting external control over high-T(C) spin ordering in diluted magnetic semiconductors.