Multiferroic properties of Aurivillius phase Bi6Fe2-xCoxTi3O18 thin films prepared by a chemical solution deposition route

The magnetic and ferroelectric properties of Co-doped Bi6Fe2Ti3O18 thin films Bi6Fe2-xCoxTi3O18 (BFCTO) (0 <= x <= 1) are investigated. The coexistence of room-temperature ferromagnetism and ferroelectricity is observed in BFCTO thin films. The x = 0.6 sample exhibits a higher remnant magnetization M-r of 8.41 emu/cm(3) and a remnant polarization P-r of 17.6 mu C/cm(2) compared with other BFCTO thin films. The ferromagnetism can be ascribed to the spin canting of Fe-and Co-based sublattices via the Dzyaloshinskii-Moriya interaction [I. Dzyaloshinsky, J. Phys. Chem. Solids 4, 241 (1958); T. Moriya, Phys. Rev. 120, 91 (1960)]. The change in the remnant polarization is discussed in terms of the variation of grain size and oxygen vacancies caused by Co-doping. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4752748]