Investigations on the EPR parameters and defect structures for Cu2+ in alkaline earth zinc borate glasses.

The electron paramagnetic resonance (EPR) parameters and defect structures for Cu 2+ in alkaline earth zinc borate glasses 10RO + 30ZnO + 60B 2 O 3 (RZB, where R = Mg, Ca and Sr) are quantitatively investigated from the consistent analysis of these parameters for a tetragonally elongated octahedral 3d 9 complex. The studied [CuO 6 ] 10− complexes are found to undergo the relative tetragonal elongation ratios of about 5.8%, 4.5% and 8.6% in MgZB, CaZB and SrZB glasses, respectively, due to the Jahn-Teller effect. The increasing tendencies (MgZB < CaZB < SrZB) of g // is attributed to the decreasing (MgZB > CaZB > SrZB) cubic field parameter Dq and increasing orbital reduction factor k , while the increasing magnitudes of hyperfine structure constants are illustrated by the increases of the reduction factor H arising from the tetragonal elongation distortions. The defect structures and the properties of the EPR parameters are discussed. [ABSTRACT FROM AUTHOR]