Fe/Pt multi-layers with modulation periods of 24.1 and 37.2Å and a [110]||[111] bcc-fcc texture were fabricated by magnetron sputtering on thermally oxidized Si wafers. The structural evolution of the multi-layers, with annealing at 300 to 600K, was studied by in situ X-ray diffraction and X-ray reflectivity. Two temperature regimes were found from the X-ray diffraction data. Below 534K slow, short-range diffusion was observed without significant broadening of the satellite peaks or changes in the texture. Above 534K fast, long-range diffusion was observed accompanied by significant broadening of the satellites and rapid increase of the misorientations of the grains. The multi-layers crystallize at about 583K into the tetragonal FePt phase with a small degree of ordering and strong [111] texture. The transition resembles a first-order phase transition with a critical exponent β = 0.48 which practically did not depend on the modulation period. The bulk interdiffusion coefficient, determined from the decay of the –1 satellite of the (001) Bragg peak of the multi-layers, could be described by:

D (m2/s) = 1.37 x 10-6 exp[-1.7(eV)/kT]

The gradient-energy coefficient k, entering the Cahn-Hilliard diffusion equation was estimated from the modulation period-dependence of the diffusion coefficient to be –6.8 x 107eV/cm.

Interdiffusion in Fe–Pt Multilayers. N.Zotov, J.Feydt, A.Savan, A.Ludwig: Journal of Applied Physics, 2006, 100[7], 073517 (11pp)