title: Intrinsic Ferromagnetism in the Diluted Magnetic Semiconductor Co:TiO_{2}.
abstract: Here we present a study of magnetism in Co_{0.05}Ti_{0.95}O_{2-δ} anatase films grown by pulsed laser deposition under a variety of oxygen partial pressures and deposition rates. Energy-dispersive spectrometry and transmission electron microscopy analyses indicate that a high deposition rate leads to a homogeneous microstructure, while a very low rate or postannealing results in cobalt clustering. Depth resolved low-energy muon spin rotation experiments show that films grown at a low oxygen partial pressure (≈10^{-6}  torr) with a uniform structure are fully magnetic, indicating intrinsic ferromagnetism. First principles calculations identify the beneficial role of low oxygen partial pressure in the realization of uniform carrier-mediated ferromagnetism. This work demonstrates that Co:TiO_{2} is an intrinsic diluted magnetic semiconductor.
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Saadaoui
authors.affiliation: School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia.
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Salman
authors.affiliation: School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: X Y
authors.initials: XY
authors.lastname: Cui
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore.
authors.forename: N N
authors.initials: NN
authors.lastname: Bao
authors.affiliation: School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Bao
authors.affiliation: School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: R K
authors.initials: RK
authors.lastname: Zheng
authors.affiliation: School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia.
authors.forename: L T
authors.initials: LT
authors.lastname: Tseng
authors.affiliation: Institute of Chemical and Engineering Science, Agency for Science, Technology and Research (A*STAR), 1 Pesek Road, Jurong Island, 627833, Singapore.
authors.forename: Y H
authors.initials: YH
authors.lastname: Du
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Prokscha
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Suter
authors.affiliation: ANKA, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Liu
authors.affiliation: School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia.
authors.forename: Y R
authors.initials: YR
authors.lastname: Wang
authors.affiliation: School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore.
authors.forename: J
authors.initials: J
authors.lastname: Ding
authors.affiliation: School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia.|The Australian Institute for Nanoscale Science and Technology, The University of Sydney, Sydney, New South Wales 2006, Australia.
authors.forename: S P
authors.initials: SP
authors.lastname: Ringer
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Morenzoni
authors.affiliation: School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia.
authors.forename: J B
authors.initials: JB
authors.lastname: Yi