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EPR Investigations on CaWO 4 :Pb Single Crystals
Author(s) -
Born G.,
Hofstaetter A.,
Scharmann A.
Publication year - 1970
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.19700370129
Subject(s) - electron paramagnetic resonance , hyperfine structure , thermoluminescence , tungstate , ion , tungsten , unpaired electron , paramagnetism , covalent bond , chemistry , crystallography , electron nuclear double resonance , nuclear magnetic resonance , materials science , luminescence , inorganic chemistry , atomic physics , condensed matter physics , physics , optoelectronics , organic chemistry
Electron paramagnetic resonance has been observed at single crystals of calcium tungstate doped with lead. After exposure to X‐ray irradiation at the temperature of liquid air paramagnetic centres appear. One group of lines originates from the V k ‐centre in the tungstates. The resonance of Pb 3+ ions at Ca 2+ sites is reported. This spectrum is characterized by a pronounced hyperfine interaction of the unpaired 6s electron of the Pb 3+ ion with the nuclear magnetic moment of the Pb 207 isotope. Superhyperfine interaction with four surrounding tungsten nuclei is observed indicating covalent bonding effects with the tungstate groups as ligands and a treatment of the complex in terms of molecular orbitals is proposed. The thermal annealing of the centres detected by EPR is correlated with the thermoluminescence glow curve.