Unique Informativity of the Diffuse Dynamical Combined Diffractometry of Materials and Products of Nanotechnologies

Abstract

In a given work, the detailed systematic analysis of the discovered phenomenon is carried out. This phenomenon of unique informativity of the dynamical-scattering pattern in crystals with many types of defects is described, its physical nature and possibilities of practical application are determined. The phenomenon nature lies in the fact that, for each reflex of the scattering pattern, while transition from kinematic case to dynamical one takes place, the dependences on conditions of dynamical diffraction are radically different from each other for Bragg and diffuse components, which always remain the same in the kinematic theory. This essential difference is caused by the substantially different nature and magnitudes of the fundamental characteristics of materials, namely, scattering factors, for Bragg and diffuse components. For the Bragg component, it is the scattering potential averaged over all defects’ configurations (periodical), and for the diffuse one, these ones are the fluctuating deviations of scattering potential from its average value (nonperiodical). As a result, the dynamical extinction factors for the coherent and diffuse-scattered waves differ from each other as well as other regularities of the multiple-scattering effects for Bragg and diffuse components. The ascertainment of a nature of the mentioned effects has provided the unique possibility of the operated change of diffuse-component contribution for the fixed defect structure just due to the purposive variation of the dynamical-diffraction conditions. The influences of defects on the Bragg and diffuse components of the scattering pattern have opposite nature, i.e. they always decrease the Bragg component, but increase the diffuse one. Due to this fact, the abovementioned phenomenon provides the possibility of the controllable variations of the total defects’ influence on the scattering pattern as a whole, which is used for its characterization. In case of the defects’ diagnostics in the dynamical diffraction conditions, this one governed the essential revision of principles of the quantitative and qualitative classification of defects by their influence on the scattering pattern, which has been performed within the scope of the kinematic theory. The possibility to control the diffuse-component contribution is the most important advantage of the dynamical diffraction, which has increased radically the informativity and has provided the fundamentally new functional possibilities of the dynamical diffractometry. The dynamical diffraction only gives the possibility of realization and combined (joint) processing of full set of the independent diffraction experiments due to the changing diffraction conditions for a sample of fixed defect structure with the goal to solve an inverse problem of the multiparametric diagnostics of crystalline materials and products of nanotechnology with several types of defects. Thus, the new generation of crystallography, i.e. the diffuse dynamical combined diffractometry of complex defect structures in single crystals and heterogeneous systems, has been developed.

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