The role of Coulomb and exchange interaction on the Dzyaloshinskii-Moriya interaction (DMI) in BiFeO3

Ab initio calculations show that the Dzyaloshinskii-Moriya interaction (DMI)and net magnetization per unit cell in BiFeO3 are reduced when U is increasing from 0 to 2.9 eV, and independent of J. Interestingly, the DMI is even destroyed as U exceeds a critical value of 2.9 eV. We propose a simple model to explain this phenomenon and present the nature of the rotation of the magnetization corresponding to altered antiferrodistortive distortions under DMI in BiFeO3. (C) 2009 Elsevier B.V. All rights reserved.