Zero-field splitting of Cr3+ in an electro-optical alpha-LiIO3 single crystal

The axial zero-field splitting (ZFS) parameter D for Cr3+ in a alpha-LiIO3 single crystal, assuming that the Cr3+ impurity locates at either Li+ or I5+ site, has been analyzed by means of the superposition model (SPM). The magnitude and sign of experimental value (D-exp) turn out to agree much better with those of theoretical D for Cr3+ at I5+ site (D-I(SPM)) than with those at Li+ site (D-Li(SPM)), respectively: D-Li(SPM) = 0.8863 cm(-1) D-I(SPM) = -0.6082 cm(-1) and D-exp = -0.6099 cm(-1) with two SPM parameters of b(2)(-0)(R-0) = 2.355 cm(-1) and t(2) = -0.60. This analysis shows that the Cr3+ impurity may enter the I5+ site. Meanwhile, our result is in contradiction to that proposed in the previous report, where the Cr3+ ion was assumed to occupy the Li+ site. This contradiction is also discussed by considering Macfalrane's method employed in that report. (C) 1997 Elsevier Science Ltd.