Grazing-incidence x-ray scattering on the $\mathrm{Cu_3Au(111)}$ phase transition

Physical review / B 37(12), 7157 - 7160 (1988). doi:10.1103/PhysRevB.37.7157
We report the results of a grazing-incidence x-ray study on the order-disorder phase transition of a (111)-oriented $Cu_3Au$ film (0.7 μm) epitaxially grown on an $Al_2O_3$ substrate with a Nb buffer layer. By varying the incident beam angles to the surface, penetration depths between 22 and 650 Å were probed. While the bulk disorders at Tb$_c$=665 K through a first-order transition, the surface region appears to exhibit an enhanced ordering with a slightly higher transition temperature. Close to Tb$_c$ pronounced short-range-order scattering is seen in the deeper layers, whereas this effect is much reduced closer to the surface.
Published by Inst., Woodbury, NY