title: Intrinsic ferromagnetism in insulating cobalt doped anatase TiO2.
abstract: Using complementary experiments we show that the room temperature ferromagnetism observed in anatase Co:TiO(2) films is not carrier mediated, but coexists with the dielectric state. TEM and x-ray absorption spectroscopy reveal a solid solution of Co in anatase, where Co is not metallic but in the +2 state substituting for Ti. Measurements at 300 K yield a M(S) of 1.1 mu(B)/Co atom, while all films are highly insulating. The evidence of intrinsic ferromagnetism in the dielectric ground state of Co:TiO(2) leads to new considerations for the origin of ferromagnetism in transition metal doped oxides.
authors.affiliation: Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Griffin
authors.forename: A B
authors.initials: AB
authors.lastname: Pakhomov
authors.forename: C M
authors.initials: CM
authors.lastname: Wang
authors.forename: S M
authors.initials: SM
authors.lastname: Heald
authors.forename: Kannan M
authors.initials: KM
authors.lastname: Krishnan