Figure 4From: First-Principles Study of Magnetic Properties of 3d Transition Metals Doped in ZnO NanowiresThe schematic view of the ferromagnetic coupling and anti-ferromagnetic coupling between the two Cr atoms doped in ZnO nanowires. The 3d levels are showed and the energy levels include thep–d interaction. The line with thedouble-headed arrow indicates that the two states with the same spin channel couple with each otherBack to article page