Specular and diffuse x-ray scattering are used to probe the mesoscopic structure of interfaces within two 30-period Mo/Si superlattices, grown on silicon and glass substrates by ion beam sputtering. The data are evaluated qualitatively and quantitatively on the basis of a distorted-wave Born approximation, which includes a correlating behavior of interface roughness in both the lateral and vertical directions. Different initial conditions of the substrate’s surface result in distinguishable characters of roughness replications in the direction of growth. The average value, lateral correlation and fractal dimension of roughness are found to be different in the two samples, which leads to differences in the reflective properties of multilayer mirrors.
A high‐resolution small‐angle X‐ray scattering camera has been built, which has the following features. (i) The point collimation optics employed allows the scattering cross section of the sample to be directly measured without corrections for desmearing. (ii) A small‐angle resolution better than 0.5 mrad is achieved with a camera length of 1.6 m. (iii) A high photon flux of 0.9 photons μs−1 is obtained on the sample with the rotating‐anode X‐ray generator operated at 40 kV–30 mA. (iv) Incident X‐rays are monochromated by a bent quartz crystal, which makes the determination of the incident X‐ray intensity simple and unambiguous. (v) By rotation of the position‐sensitive proportional counter around the direct beam, anisotropic scattering patterns can be observed without adjusting the sample. Details of the design and performance are presented with some applications.
The crystallite orientation and lamellar deformation produced by hot‐rolling in polyethylene have been investigated. In the lightly rolled stage, the [110]* axis of polyethylene crystals orientates in the plane perpendicular to the rolling direction and the c axis becomes aligned with the rolling direction. In the heavily rolled stage the a, b, and c axes coincide with the macroscopic directions in the sample. These orientational changes are interpreted in terms of a slip mechanism. Small‐angle x‐ray scattering (SAXS) investigations of hot‐rolled polyethylene show the following. (1) There are two kinds of lamellar structures; one in which inclined lamellae give a four‐point diagram in the SAXS photograph and another in which lamellar normals are oriented around the rolling direction even at the lightly rolled stage. The latter structure is attributed to the mechanism of unfolding and recrystallization. (2) The chain‐fold length in the original structure remains unchanged in the lamellae up to a roll ratio of four although the apparent long period decreases. This is explained by inclination of polymer chains in the lamellae. Further rolling aligns the polymer chains with the rolling direction and the fold length decreases.
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