Structural evolution and second harmonic properties of lithium niobate-tantalate nanocrystals embedded in a borate glass

Jaschin, PW and Varma, KBR (2016) Structural evolution and second harmonic properties of lithium niobate-tantalate nanocrystals embedded in a borate glass. In: JOURNAL OF NON-CRYSTALLINE SOLIDS, 434 . pp. 41-52.

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Abstract

Nano-crystals of LiNbxTa1 (-) O-x(3) were evolved by subjecting melt-quenched 1.5Li(2)O-2B(2)O(3)-xNb(2)O(5)-(1 - x)Ta2O5 glasses (where x = 0, 0.25, 0.5, 0.75 and 1.00) to a controlled 3-h isothermal heat treatment between 530 and 560 degrees C. Detailed X-ray diffraction and Raman spectral studies confirmed the formation of nano-crystalline LiNbxTa1 (-) O-x(3) along with a minor phase of ferroelectric and non-linear optic Li2B4O7. The sizes of the nanocrystals evolved in the glass were in the range of 19-37 nm for x = 0-0.75 and 23-45 nm for x = 1.00. Electron microscopic studies confirmed a transformation of the morphology of the nano-crystallites from dendritic star-shaped spherulites for x = 0 to rod-shaped structures for x = 1.00 brought about by a coalescence of crystallites. Broad Maker-fringe patterns (recorded at 532 nm) were obtained by subjecting the heat-treated glass plates to 1064 nm fundamental radiation. However, an effective second order non-linear optic coefficient, d(eff), of 0.45 pm/V, which is nearly 1.2 times the d(36) of KDP single crystal, was obtained for a 560 degrees C/3 h heat-treated glass of the representative composition x = 0.50 comprising 37 nm sized crystallites. (C) 2015 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	JOURNAL OF NON-CRYSTALLINE SOLIDS
Publisher:	ELSEVIER SCIENCE BV
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Keywords:	Glass nanocrystal composites; Lithium niobate; Lithium tantalate; Second harmonic generation; Coalescence
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	02 Apr 2016 09:50
Last Modified:	02 Apr 2016 09:50
URI:	http://eprints.iisc.ac.in/id/eprint/53470

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