Effect of capping ligands on the synthesis and on the physical properties of the nanoparticles of $LiTaO_3$

Satapathya, S and Gupta, PK and Srivastava, Himanshu and Srivastava, A.K and Wadhawan, VK and Varma, K.B.R and Sathe, VG (2007) Effect of capping ligands on the synthesis and on the physical properties of the nanoparticles of $LiTaO_3$. In: Journal of Crystal Growth, 307 (1). pp. 185-191.

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Abstract

This paper reports the synthesis of lithium tantalate $(LiTaO_3)$ nanoparticles by a sol–gel process involving the use of capping ligands. When the sol was allowed to form gel and then annealed at $600^oC$ for 1 h in the presence of oxygen, hexagonal crystallites of size $2–5 \mu m$ were formed. But when the sol was heat treated at $600^oC$ for 1 h in the presence of oxygen before gelation, agglomerated nanoparticles were formed. The addition of aniline before gelation (a neutral capping ligand with N-donor atom) not only restricted gelation, but also helped in the formation of well-separated and irregular nanoparticles of sizes 40–70 nm, which was confirmed from TEM and XRD studies. The anionic-ligand oleic acid (lipophilic ligand with O-donor atoms) restricted gelation by arresting the surface of $LiTaO_3$, and spherical nanoparticles of size 20–40nm were formed after heating the sol. Comparison of ferroelectric and dielectric properties between bulk particle and spherical nanoparticles (obtained using oleic acid) are reported by characterizing these particles using Raman spectroscopy and differential scanning calorimetry (DSC). The Curie temperature decreases with decreasing the particle size of $LiTaO_3$.

Item Type:	Journal Article
Publication:	Journal of Crystal Growth
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier.
Keywords:	Differential scanning calorimetry;Scanning electron microscope;Transmission electron microscope;X-ray diffraction;Nanomaterials;Ferroelectric materials.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	01 Aug 2008
Last Modified:	19 Sep 2010 04:48
URI:	http://eprints.iisc.ac.in/id/eprint/15343

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