%0 Journal Article
%A Mavropoulos, Ph.
%A Lezaic, M.
%A Blügel, S.
%T Ferromagnetism in nitrogen-doped MgO: Density-functional calculations
%J Physical review / B
%V 80
%N 18
%@ 1098-0121
%C College Park, Md.
%I APS
%M PreJuSER-6326
%P 184403
%D 2009
%Z Record converted from VDB: 12.11.2012
%X 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.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000272310900061
%R 10.1103/PhysRevB.80.184403
%U https://juser.fz-juelich.de/record/6326