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Influence of oxygen on electrical properties of CaF 2 crystals
Author(s) -
Švantner M.,
Mariani E.
Publication year - 1978
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19780131209
Subject(s) - raw material , electrical resistivity and conductivity , impurity , materials science , moisture , oxygen , ion , doping , crystal (programming language) , pyrolysis , analytical chemistry (journal) , mineralogy , chemical engineering , composite material , chemistry , optoelectronics , environmental chemistry , organic chemistry , electrical engineering , computer science , programming language , engineering
Abstract The O 2− ions appear as an unwanted impurity that contaminates the crystals of alkaline and rare earth fluorides during their preparation. The easy incorporation into the lattice and difficulties with their detection make the measurement of electrical properties problematical. In order to elucidate the influences of oxygen on CaF 2 crystals we have measured electrical conductivity. The crystals were prepared from a raw material of various moisture content, or they were doped by CaO, respectively. The measured courses exhibit equal activation energy E = 0.64 eV in the middle range. We thus conclude that synthetizing the crystal contaminated by moisture yields incorporation of O 2− ions only. We proved that even a two hours delay of melted raw material in gaseous products of Teflon pyrolysis does not suffice to remove oxygen. The method is effective only when applied after drying of raw material in vacuum.