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Effect of Halide Ions on the Electronic Conductivity in Calcium Borate Glasses
Author(s) -
Gohar I. A.,
Assem E. E.,
Abuelela A.
Publication year - 1993
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.2170280114
Subject(s) - halide , boron , ion , halogen , electrical resistivity and conductivity , inorganic chemistry , chemistry , doping , analytical chemistry (journal) , thermal conduction , materials science , physics , alkyl , optoelectronics , organic chemistry , chromatography , composite material , quantum mechanics
Some halogen‐doped calcium borate glasses containing iron have been prepared according to the percentage molar composition [(30 – x ) CaO · x CaX 2 · 10 Fe 2 O 3 · 60 B 2 O 3 ] and annealed. It is found that the conduction in the semiconducting glasses is mainly due to electronic conduction. The results show that the halide ions may be introduced as modifiers for CaX 2 concentration < 10 mol% (X >= F, Cl, and Br) but they are network formers at CaX 2 > 10 mol%. It is proposed that at 10 mol% the network structure for all glasses seems to be the same. The dependence of resistivity on the halide ions concentration as well as the slight variation of activation energies, could be explained on the basis of electron‐lattice interaction. Mathematical expressions for fitting and describing the dependence of resistivity on CaX 2 concentration are deduced and formulated by the following equations: ϱ = ϱ 0 exp [± ac (1 – bc )] and ϱ ϱ= ± 10 exp [± a′c (1 – b′c )] for the two regions around the critical concentration.