title: Defect controlled room temperature ferromagnetism in Co-doped barium titanate nanocrystals.
abstract: Defect mediated high temperature ferromagnetism in oxide nanocrystallites is the central feature of this work. Here, we report the development of room temperature ferromagnetism in nanosized Co-doped barium titanate particles with a size of around 14 nm, synthesized by a solvothermal drying method. A combination of x-ray diffraction with state-of-the-art electron microscopy techniques confirms the intrinsic doping of Co into BaTiO3. The development of the room temperature ferromagnetism was tracked down to the different donor defects, namely hydroxyl groups at the oxygen site (OH·(O) and oxygen vacancies (V··(O), and their relative concentrations at the surface and the core of the nanocrystal, which could be controlled by post-synthesis drying and thermal treatments.
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.
authors.forename: Sugata
authors.initials: S
authors.lastname: Ray
authors.forename: Yury V
authors.initials: YV
authors.lastname: Kolen'ko
authors.forename: Kirill A
authors.initials: KA
authors.lastname: Kovnir
authors.forename: Oleg I
authors.initials: OI
authors.lastname: Lebedev
authors.forename: Stuart
authors.initials: S
authors.lastname: Turner
authors.forename: Tanushree
authors.initials: T
authors.lastname: Chakraborty
authors.forename: Rolf
authors.initials: R
authors.lastname: Erni
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Watanabe
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Van Tendeloo
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoshimura
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Itoh