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Research of the Central Core in Bi 12 SiO 20 Crystals
Author(s) -
Gospodinov M.,
Tassev V.,
Dimitrov K.
Publication year - 1996
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170310511
Subject(s) - core (optical fiber) , facet (psychology) , impurity , dopant , materials science , projection (relational algebra) , absorption (acoustics) , crystallography , laser , optics , doping , chemistry , optoelectronics , physics , composite material , computer science , big five personality traits , psychology , social psychology , organic chemistry , personality , algorithm
The structure of the so‐called “central core” within Czochralski grown Bi 12 SiO 20 crystals is investigated by the laser projection. A finer structure with a number of optical inhomogeneities with irregular forms and sizes about 2–3 μm is observed within the core. The conditions for facet growth and absorption of impurities on the facets are described. Positron lifetime measurements are carried out within and outside the core. The results show a higher concentration of defects in regions within the core. The optical rotatory power in regions within and outside of the core was measured, too. An evaluation of the distribution of the different structural units and the dopants is made. Some suppositions about the kind and the role of the defective center are given.