Abstract
Large crystal growths of the Eu2+-doped spatially coherent [KBr0.097I0.903](0.348):[KBr0.459Cl0.511I0.030](0.652) composite were characterized by X-ray diffraction and then studied by epifluorescence optical microscopy. Doping Eu2+ ions were observed to prefer sites located at certain linear structural singularities of the composite matrix to be segregated at. These singularities (2.1 × 107 singularities cm−2), identified as crystal lattice dislocations, were found to be distributed within the composite matrix so that they form periodic arrays of linear structural singularities (1.8 × 104 singularities cm−1). These arrays, identified as grain sub-boundaries, were found to envelope individual structural domains (1–5 µm in size) of either KBr0.459Cl0.511I0.030:Eu2+ or KBr0.097I0.903:Eu2+. These domains were found to aggregate among themselves to form the whole composite building. Small misfit angles (e.g. 7′ ± 1′ and 10′ ± 1′) characterize homo-phase structural domains while large misfit angles are characteristic of hetero-phase structural domains. Crystal lattice dislocations, forming the grain sub-boundaries, were found to present, as structural features, kinks and bifurcation points. The spatial configurations adopted by two of these features are carefully described.
Acknowledgements
This study was partially supported by Dirección General de Asuntos del Personal Académico de la Universidad Nacional Autónoma de México (project DGAPA-PAPIIT IN112409). The author thank Mr I. Camarillo for providing the composite material and Mr R. Unda-Angeles for doing the fluorescence image computational treatment, and, also for preparing the europium-decoration three-dimensional maps.