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A Hole Center Causing Rose Coloration in AlPO 4 and GaPO 4
Author(s) -
Requardt A.,
Lehmann G.
Publication year - 1985
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.2221270232
Subject(s) - thermoluminescence , electron paramagnetic resonance , activation energy , chemistry , hyperfine structure , valence (chemistry) , atomic physics , analytical chemistry (journal) , materials science , luminescence , nuclear magnetic resonance , physics , optoelectronics , chromatography , organic chemistry
In synthetic AlPO 4 crystals and Sn‐doped GaPO 4 hole centers localized on an oxygen showing an almost isotropic hyperfine splitting from a 31 P nucleus are observed after X‐ray irradiation and analyzed by EPR. They are evidently caused by substitution of Al and Ga, respectively, by a divalent cation, most likely Mg 2+ . From the variation of the EPR linewidths with temperature an activation energy of 19 kJ/mole for thermal hopping of the hole is found in AlPO 4 . These centers cause a rose coloration and the first absorption band in AlPO 4 has an oscillator strength near 0.3, in the same range as for the smoky quartz centers. It is interpreted as arising from optical transfer of the hole within the PO 4 unit. Thermoluminescence emission is observed with destruction of the centers in AlPO 4 . From glow curves an activation energy of 136 kJ/mole is obtained which in this case represents the distance of the hole from the valence band. The properties of the center in AlPO 4 are compared to those of a similar center in certain natural rose‐colored quartz crystals.