Dolzhenkova E. Borate single crystals: real structure and physical properties

Object: the processes of defect formation in сomplex oxide crystals under ionizing irradiation and mechanical stresses. The purpose: establishment of crystallographic criteria of stability for borate compounds of different structural types under external factors such as ionizing irradiation and mechanical stresses for development of scientific foundations for the creation of materials for detectors based on these crystals. Methods: X-ray diffraction structural and phase analyses, atomic emission spectral analysis, the differential thermal analysis, microhardness method, optical spectroscopy, photo-, X-ray- and thermostimulated luminescence. Results: the cleavage systems and dominating crack propagation in borate single crystals of different structural types are established. Established is the nature of destruction of borate compounds with finite, chained, layered and framework types of polianion, the weakest bonds in crystal lattices are defined. A strong temperature dependence of plasticity of borates is established; plastic flow in these crystals starts at Т=0.9Тmelt. The nature of radiation-induced point defects in borate single crystals of different structural types is determined. Built are the models of electron and hole trap centers. The mechanism of creation of stable interstitial-vacancy pairs in cation sublattice is proposed. Field of application: physics of solid state, physics of semiconductors and dielectrics, optics