Nabi, Hasan Sadat; Pentcheva, Rossitza (2010): Origin of Interface Magnetism in Fe(2)O(3)/FeTiO(3) Heterostructures. In: Wagner, S.; Steinmetz, M.; Bode, A.; Muller, M. M. (Hrsg.): HIGH PERFORMANCE COMPUTING IN SCIENCE AND ENGINEERING, GARCHING/MUNICH 2009: TRANSACTIONS OF THE FOURTH JOINT HLRB AND KONWIHR REVIEW AND RESULTS WORKSHOP. S. 565-574
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Nanoscale exsolutions of the canted antiferromagnet hematite(alpha-Fe(2)O(3)) and the room temperature paramagnet ilmenite(FeTiO(3)) show a surprisingly stable room temperature remanentmagnetization, making the material interesting for spintronicsapplications. To understand the nature of this phenomenon at the atomicscale, density functional theory calculations with an on-site Coulombrepulsion parameter were performed on Fe(2-x)Ti(x)O(3), varying theconcentration, distribution and charge state of cations. We find thatthe polar discontinuity at the interface is accommodated by theformation of a mixed Fe(2+)/Fe(3+) layer. The uncompensated interfacemoments give rise to ferrimagnetism in this system. We also explore theeffect of strain, showing that it can be used to tune the electronicproperties (e.g. band gap, position of impurity levels). Furthermore, wefind that epitaxial growth on an Al(2)O(3)(0001) substrate isenergetically unfavorable compared to substrates with a larger laterallattice parameter, providing thereby a guideline for an optimal choiceof the substrate in growth experiments.