An approach to reduce the antiferromagnetic coupling of antiphase boundaries in half-metallic magnetite films

摘要

Highly conductive (~10~5μΩ cm) Mn doped epitaxial Fe_3O_4 films were fabricated by reactive sputtering. The larger size of magnetic domains compared to grain size with the increasing Mn content indicates that the partial antiferromagnetic coupling across the antiphase boundaries has been weakened, which was further demonstrated by the smaller exchange bias, faster saturated magnetization, and decreasing exchange interaction J_(AF). The decrease of antiferromagnetic strength originates from the larger Mn-O bond length than that of Fe-0 bond. The first-principle calculation shows that the half-metallic feature (100% spin polarization) of Fe_3O_4 was unchanged with the incorporation of Mn atoms.