Universal Journal of Materials Science 1(2): 18-24, 2013 http://www.hrpub.org DOI: 10.13189/ujms.2013.010202 Preparation of Lithium Niobate Nanoparticles by High Energy Ball Milling and their Characterization Sujan Kar 1 , Shweta Logad 2 , Om P Choudhary 3 , Chiranjit Debnath 1 , Sunil Verma 1 , Kunwar S Bartwal 1,* 1 Laser Materials Development & Devices Division, RRCAT, Indore- 452013, India 2 Department of Physics, Vikram University, Ujjain, India 3 Department of Applied Physics, GSITS, Indore- 452003, India *Corresponding Author: bartwalks@yahoo.co.in Copyright © 2013 Horizon Research Publishing All rights reserved. Abstract We present investigations on the preparation of lithium niobate, LiNbO3 nanoparticles using high energy ball-milling. Stoichiometric composition of LiNbO3 powder was prepared by solid-state reaction method and used for ball-milling. Various milling parameter were optimized to get required particle sizes. Synthesized nanoparticles were characterized for their structure and particle sizes using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The UV-Visible transmission shows the blue shift in cutoff, which indicate nearly stoichiometric composition of the prepared material. It has been observed that the sizes of particles decreases with increasing milling speed and time. Observed particle sizes were found in the range ~30-60 nm. Keywords Nanoparticles; Ball-milling; Lithium niobate; XRD; TEM; Transmission 1. Introduction Lithium niobate, LiNbO 3 crystal is one of the most versatile synthetic materials. It is negative uniaxial, highly birefringent and has remarkable combination of piezoelectric and optical properties. These properties makes LiNbO 3 , a technologically important material, particularly as a non-linear optical, electro-optical, and related interdisciplinary fields [1-3]. In the past decade, significant interest has been focused on the synthesis of nanoscale materials due to their interesting properties emerging from the dimensional confinement, and has great potential for device applications. Nanocrystalline particles either pure or embedded into a suitable host material show new physical effects [4, 5]. As size reduces into nanometer range, the material exhibit interesting mechanical and physical properties, e.g. increased mechanical strength, enhanced diffusivity, higher specific heat and electrical resistivity compared to conventional coarse grained counterparts. The unique features of nano-sized piezo ferroelectrics, pyro ferroelectrics, and ferroelectrics enable a broad spectrum of thermo-electrical, electro-mechanical, electronic, and dielectric properties for sensors and actuators, compact electronics, pyro sensors, and thermal imaging [6, 7]. Piezoelectric nanowires have been studied as potential strain-based energy harvesting devices e.g. direct current generators [8-10]. The rapid progress in synthesis of ferroelectrics nanoparticles, in particular vertical arrays of free-standing tubes, wires and rods in porous template demonstrated their enhanced polar properties and unusual domain structure [11-14]. It has been reported that the pyroelectric coefficient increases strongly as the wire radius decreases and diverges at critical radius R cr corresponding to size driven transition into paraelectric phase [15]. Size driven enhancement in pyroelectric coupling leads to giant pyroelectric current and voltage generation by polarized ferroelectric nanoparticles in response to the temperature fluctuation. The size effect can be used to tune the phase transition temperature in ferroelectric nanostructure, thus enabling the system with tunable giant pyroelectric response. Many synthesis routes are being developed for LiNbO 3 at the nanoscale resulting in different size, shape, and crystalline quality. LiNbO 3 nanoparticles have been previously produced by milling [16] non-aqueous route [17] sol-gel method [18] or hydrothermal route [19]. Polycrystalline LiNbO 3 nanotubes have also been reported [20] as well as a solution-phase synthesis to produce rod like structures among other multiple structures [21]. This enhancement is related to larger drift length of the photo-holes (lifetime) due to trapping of electrons on the nanoparticles and creation of recombination barrier at the polymer/nanoparticle interface at higher nanoparticle concentration. In this paper we report the preparation of lithium niobate, LiNbO 3 nanoparticles by high energy ball milling. The milling parameters were optimized for obtaining the desired phase and particle size. The prepared particles were characterised for phase, crystallinity and sizes using powder XRD, SEM, TEM and dynamic light scattering (DLS)