First-principles study of electronic and magnetic properties in Co doped BaTiO3

The electronic and magnetic properties of Co doped BaTiO3 have been investigated using the first-principle calculations within density functional theory. The nature of magnetism is mainly from the dopant Co atom with magnetic moment 3.15 mu(B), suggesting the Co impurity atom with a high-spin configuration. With the increasing doping concentration, there exist mid-gap states at the Fermi level that increases the probability of electron transitions from valence band to conduction band. On the other hand, the O vacancy has a significant influence on the electronic and magnetic properties in doped BaTiO3 systems. The presence of O vacancy leads to the elapse of system magnetism from 4.78 mu(B) to 1.0 mu(B), indicating the transition of the spin configuration of Co atom from a high-spin state to a low-spin one. The results are in good agreement with the experimental observations.