@article { ISI:000272310900061,
	title = {Ferromagnetism in nitrogen-doped MgO: Density-functional calculations},
	journal = {PHYSICAL REVIEW B},
	volume = {80},
	number = {18},
	year = {2009},
	month = {NOV},
	pages = {184403},
	abstract = {The magnetic state of nitrogen-doped MgO, with N substituting O at concentrations between 1\% and the concentrated limit, is calculated with density-functional methods. The N atoms are found to be spin polarized with a moment of 1 mu(B) per nitrogen atom and to interact ferromagnetically via the double-exchange mechanism in the full concentration range. The long-range magnetic order is established above a finite concentration of about 1.5\% when the percolation threshold is reached. The disorder is described within the coherent-potential approximation, with the exchange interactions harvested by the method of infinitesimal rotations. The Curie temperature T-C, calculated within the random-phase approximation, increases linearly with the concentration, and is found to be about 30 K for 10\% concentration. Besides the substitution of single nitrogen atoms, also interstitial nitrogen atoms, dimers and trimers, and their structural relaxations are discussed with respect to the magnetic state. Possible scenarios of engineering a higher Curie temperature are analyzed, with the conclusion that an increase in T-C is difficult to achieve, requiring a particular attention to the choice of chemistry.},
	issn = {2469-9950},
	doi = {10.1103/PhysRevB.80.184403},
	author = {Mavropoulos, Phivos and Lezaic, Marjana and Bl{\"u}gel, Stefan}
}
