Diffusion of Fe atoms in a thin FePt film of L10 structure was investigated in the low temperature region where Fe diffusivities were between 10-22 and 10-24m2/s (figure 2). A new method using nuclear resonant scattering of synchrotron radiation in grazing incidence geometry was used, providing higher accuracy and sensitivity than the conventional tracer methods. Isotopic FePt multilayer samples Pt20Å∕[57FePt20Å∕FePt30Å]10∕MgO(001) produced by molecular beam epitaxy were annealed at 4 temperatures between 773 and 873K for between 1 and 2h. The nuclear reflectivity was measured at room temperature after each annealing step and the decrease of the nuclear superstructure Bragg-peak intensities was observed. From the intensity loss, the diffusion coefficient and the activation energy for Fe self-diffusion in the FePt thin film along the c-axis were determined as D0= 3.45 x 10-13m2/s and Q = 1.65eV. The value for the activation energy was the same as found by residual resistivity measurements in the same system.

Self-Diffusion of Iron in L10-Ordered FePt Thin Films. M.Rennhofer, B.Sepiol, M.Sladecek, D.Kmiec, S.Stankov, G.Vogl, M.Kozlowski, R.Kozubski, A.Vantomme, J.Meersschaut, R.Rüffer, A.Gupta: Physical Review B, 2006, 74[10], 104301 (8pp)