Theoretical studies on the influence of oxygen impurity upon magnetic properties of (Ga,Cr)N

Abstract We have studied the influence of O impurities upon magnetic properties of (Ga,Cr)N by using first-principles calculations based on the density-functional theory. Although the magnetic moment per Cr atom is enhanced, the ferromagnetic exchange interaction between Cr spins is reduced by co-doping with O into (Ga,Cr)N. In particular, the reduction is remarkable when the doped O atom forms a Cr–O–Cr complex. The role of O impurity is similar to that of N vacancy ( V N ), however, the O impurities could degrade the ferromagnetic stability of (Ga,Cr)N more seriously than the N vacancies since the formation energy of the Cr–O–Cr complex is much lower than that of the Cr– V N –Cr complex.