Reichert et al. Reply: In our work [1] we have been able for the first time to separate the chemical and straininduced parts of the effective interactions in a binary alloy using experimental data. In particular, we show that the long-range tail of the atomic interactions in the Cu-Mn system is of strain-induced origin. We demonstrated that in the Cu-Mn alloy strain-induced effects caused by atomic size mismatch manifest itself in the atomic interactions and in the diffuse scattering at small momentum transfer. In particular, the long-range oscillatory tail of the effective pair interaction (EPI) is quite accurately described by the strain-induced interaction ( Fig. 1 in [1]). In our calculation we used a short-ranged chemical interaction in four coordination shells deduced from the total EPI given in Ref. [2] together with the strain-induced interaction described in reciprocal space and taking into account its well-known nonanalyticity. Being in perfect agreement with corresponding experimental data these calculations showed that the azimuthal anisotropy in the diffuse scattering pattern near the origin of the reciprocal space is of strain-induced nature. At the same time, the approach allows a reasonable extrapolation to the G point.In the Comment [3] it is stated that it is not correct to conclude a nonanalyticity at the G point having not studied that point and its immediate vicinity. We want to point out that it is just this well-known fact that the G point cannot be accessed experimentally which poses a serious challenge to improve theoretical and experimental methods such that the behavior of the interactions and the related diffuse scattering at the G point can reliably be deduced from an extrapolation to this point. We have performed such a study in Ref.[1] and further support it in the following by additional experimental evidence.We have carried out a synchrotron x-ray scattering study of Cu 83 Mn 17 at beam line ID15B of the European Synchrotron Radiation Facility (Grenoble) and recorded additional two-dimensional diffuse scattering patterns with better resolution around the G point. In Fig. 1 we show the experimental data reaching q 0.15 reciprocal lattice units along two different high-symmetry lines (along X-G and K-G, respectively) together with the results of model calculations detailed in [1]. The model calculations reproduce the behavior of the diffuse intensity in the whole Brillouin zone perfectly. Note that there are no free parameters in our calculations. It is obvious that the observed diffuse 209604-1

Face-centered cubic single crystals of = 1.55 m diameter hard-sphere silica colloidal particles were prepared by sedimentation onto ͑100͒ and ͑110͒ oriented templates. The crystals had a wide interface with the overlaying liquid that was parallel to the template. The location of the interface was determined by confocal microscopic location of the particles, followed by identification of the crystalline and liquid phases by a bond-orientation order parameter. Fluctuations in the height of the interface about its average position were recorded for several hundred configurations. The interfacial stiffness ␥ was determined from the slope of the inverse squared Fourier components of the height profile vs the square of the wave number, according to the continuum capillary fluctuation method. The offset of the fit from the origin could quantitatively be accounted for by gravitational damping of the fluctuations. For the ͑100͒ interface, ␥ = ͑1.3Ϯ 0.3͒k B T / 2 ; for the ͑110͒ interface, ␥ = ͑1.0Ϯ 0.2͒k B T / 2 . The interfacial stiffness of both interfaces was found to be isotropic in the plane. This is surprising for the ͑110͒, where crystallography predicts twofold symmetry. Sedimentation onto a ͑111͒ template yielded a randomly stacked hexagonal crystal with isotropic ␥ = 0.66k B T / 2 . This value, however, is less reliable than the two others due to imperfections in the crystal.

No abstract

No abstract

We have measured and theoretically analyzed the diffuse scattering in the binary alloy system Au-Ni, which has been proposed as a testing ground for theories of alloy phase stability. We found strong evidence that in the alloys Au3Ni and Au3Ni2, fluctuations of both ordering- and clustering-type are competing with each other. Our results resolve a long-standing controversy on the balance of relaxation and mixing energies in this alloy system and explain recent findings of ordering in thin Au-Ni films.