title: Study of reorientation processes in L10-ordered FePt thin films.
abstract: We report on the development of structural and magnetic order in epitaxially grown L10FePt thin films. Upon annealing, the easy axis of magnetization changes from the out-of-plain into the in-plain direction. We found that the overall fraction of reoriented domains first increases but after certain time decreases before achieving a saturated state. The results are based on conversion electron Mössbauer spectroscopy studies and confirm Monte Carlo simulations in nano-layered FePt. We present a modified version of the Johnson-Mehl-Avrami (JMA) model adequately describing the experimental findings. Two dynamical processes, the first being a 2D-growth, dominate the initial state of sample annealing and the second being a 3D-growth, dominate the late stage close to saturation. From an Arrhenius plots of JMA coefficients for both processes we extracted the activation energies of the underlying dynamics which are 1.5(1) eV for disordering and 0.8(2) eV for ordering.
authors.affiliation: Dynamics of Condensed Systems, Faculty of Physics, University of Vienna, Strudlhofgasse 4, A-1090 Wien, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Rennhofer
authors.affiliation: M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Kozlowski
authors.affiliation: Instituut voor Kern- en Stralingsfysica and INPAC, K.U.Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Laenens
authors.affiliation: Dynamics of Condensed Systems, Faculty of Physics, University of Vienna, Strudlhofgasse 4, A-1090 Wien, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Sepiol
authors.affiliation: M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland.
authors.forename: R
authors.initials: R
authors.lastname: Kozubski
authors.affiliation: Instituut voor Kern- en Stralingsfysica and INPAC, K.U.Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Smeets
authors.affiliation: Instituut voor Kern- en Stralingsfysica and INPAC, K.U.Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Vantomme
keywords: A. Magnetic intermetallics; B. Order/disorder transformations; C. Thin films; F. Spectroscopic methods; G. Magnetic applications