New Transition Metal Phosphates Related to KTiOPO4. Synthesis of K0.5M0.5M′0.5OPO4 (M = Nb, Ta; M′ = Ti, V) and K1-xTi1-xVxOPO4 Exhibiting Nonlinear Optical Behavior
✍ Scribed by J. Gopalakrishnan; K.Kasthuri Rangan; B.Raghavendra Prasad; C.K. Subramanian
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 294 KB
- Volume
- 111
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
Several transition metal phosphates of the general formula (\mathrm{K} M_{0.5} M_{0.5}^{\prime} \mathrm{OPO}{4}), where (M=\mathrm{Nb}^{\mathrm{V}}) or (\mathrm{Ta}^{\mathrm{V}}) and (M^{\prime}=\mathrm{Ti}^{\mathrm{II}}), (\mathrm{V}^{\mathrm{II}}), (\mathrm{Cr}^{\mathrm{II}}), (\mathrm{Fe}^{\mathrm{ll}}), possessing the (\mathrm{KTiOPO}{4}(\mathrm{KTP})) structure have been synthesized. Unlike KTP, none of these phosphates exhibit second harmonic generation (SHG) of the 1064-nm radiation. Soft-chemical oxidation of the (\mathrm{Ti}^{\mathrm{II}}) and (\mathrm{V}^{\mathrm{HII}}) phosphates using chlorine in (\mathrm{CHCl}{3}), however, restores the SHG property to the oxidized materials, (\mathrm{K}{0.5} M_{0.5} M_{0.5}^{\prime} \mathrm{OPO}{4}\left(M=\mathrm{Nb}^{\mathrm{v}}, \mathrm{Ta}^{\mathrm{v}} ; M^{\prime}=\mathrm{Ti}^{\mathrm{IV}}, \mathrm{V}^{\mathrm{IV}}\right) . \mathrm{K}{1-x}) (\mathrm{Ti}{1-x} \mathrm{~V}{x} \mathrm{OPO}{4}(x \leq 0.25)) prepared similarly from (\mathrm{KTi}{1-x} \mathrm{~V}{x} \mathrm{OPO}{4}) also exhibit SHG. The results reveal that exclusive presence of (d^{0}) cations at the (\mathrm{Ti}^{\mathrm{IV}}) site preserves the SHG response of KTP derivatives. 1994 Academic Press, Inc.