Oxygen vacancies and ferromagnetism in CoxTi1−xO2−x−y

摘要: Cobalt-doped titanium dioxide, or CTO, has emerged in the past 2 years as a semiconducting, transparent, room-temperature ferromagnet. Very recently it been shown that magnetism CTO often originates surface nanoparticles Co-rich regions have much-enhanced substitutional Co content up to 40% of Ti sites, so magnetic is not true dilute semiconductor (DMS), but rather fairly high-density spin system. In this work we describe computational study using generalized gradient approximation density functional theory within supercell model. Our total energy calculations show strong tendency for Co-atom clustering segregation on sites. There also oxygen vacancies form complexes with atoms. addition, find stoichiometry plays an essential role determining system’s order. The largest ordered moments require at least enough put all C...