Abstract Details

Modeling of Texture Effect on 2d Diffraction Patterns
Abstract ID	MAT-19
Presenter	Luis  Fuentes-Montero
Presentation Type	Poster
Full Author List	L. Fuentes-Montero (1) , L. Fuentes-Cobas (1)
Affiliations	(1) Advanced Materials Research Center, Chihuahua, Mexico
Category	Materials Science
Abstract	After measuring two-dimensional (2D) diffraction/scattering patterns, researchers face the task of identifying and indexing the obtained collections of diffraction signals. This interpretation process may be facilitated by the simultaneous computer-aided modeling of crystal orientation or polycrystalline sample texture, associated stereographic projection and corresponding diffraction spots or arcs. Present poster describes recent developments in software “Analeu”, introduced in the 2006 SSRL Users Meeting. Present version of “Anaelu” models, in four different screen fields, a representative crystal unit cell in a given orientation, the corresponding stereographic projection, the allowed diffraction peaks in a hypothetical area detector and —the most important— a comparison between modeled and experimental diffraction patterns. Poly- and monochromatic radiations are allowed. The user inputs crystal structure (keyboard), rotation angles (mouse or keyboard) and experimental parameters (keyboard). The program represents the rotated crystal, shows the associated stereographic projection and predicts observable diffraction maxima. As the user rotates the crystal model, the stereographic projection and the diffraction pattern transform in real time. Comparison of the symmetry properties of the stereographic projection and the diffraction spots may play an important role in pattern indexation. Lattice parameters may also be varied in real time. Recent progress in the program refers to texture modeling. By means of programmed crystal rotation, Anaelu simulates the diffraction pattern of fibre-symmetry orientation distributions. The user chooses the axial symmetry rotation axis, the rotation angle domain, the step and tolerance. The program executes the rotation program, predicts and plots the 2D diffraction pattern and allows comparison among calculated and observed signals. A practical application of the software is shown. The diffraction pattern produced by a collection of PbTiO3 quantum dots, deposited over a SrTiO3 substrate, is simulated, compared with experiment and positively identified. Software “Anaelu” is available, free of charge, at http://www.cimav.edu.mx
Footnotes
Funding Acknowledgement	Portions of this research were carried out at SSRL, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. Support by Consejo Nacional de Ciencia y Tecnología, Mexico (Project 46515) is acknowledged.