Effect of dopant and DC bias potential on dielectric properties of polyvinyl alcohol (PVA)/PbTiO 3 - composite films Girish M. Joshi a, * , S.M. Khatake a , S. Kaleemulla a , N. Madhusudhana Rao a , Teresa Cuberes b a Material Science Division, School of Advanced Sciences, VIT University, Vellore-632014, TN, India b Laboratory of Nanotechnology (LNN), University of Castilla-La-Mancha (UCLM), Almadén, Spain article info Article history: Received 18 October 2010 Received in revised form 24 March 2011 Accepted 25 March 2011 Available online 1 April 2011 Keywords: Polymer composite film Dielectric In and out plane DC bias potential abstract Composite films of Polyvinyl alcohol (PVA) mixed with Lead Titante Oxide (PbTiO 3 ) were prepared. Dopant incorporated and DC bias induced electrical parameters were disclosed with respect to pure PVA film. The results demonstrate dielectric polarization is not only directly proportional to PbTiO 3 % of dopant but also external DC bias potential at 30  C based on Maxwell Wagner theory. Hence these properties highly applicable as super-capacitor film and humidity sensor applications. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction The smart memory alloy made up of ferroelectric ceramic functions on the principle of piezo-electricity. It exhibit impulse response by deformation under external electrical or mechanical field. BaTiO 3 , PbTiO 3 , SrTiO 3 , CaTiO 3, CsNO 3 belong to the class of pervoskite material, highly useful for electronics industry due to dielectric, piezo-electric and ferroelectric properties and sustain- able at high temperature. Therefore it is used in the area of fabri- cation of thin film electronic components, tailoring percolative capacitors and optoelectronic devices [1e3]. The poled crystal of PbTiO 3 in composition with Mg and Nd oxides demonstrate temperature independent dielectric and piezo-electric properties applicable to design a device operable at cryogenic conditions [4]. PbTiO 3 is having the transition temperature (T C ) 490  C and high value of dielectric constant [5]. The comparative study of PbTiO 3 doped ionic entities show effect on its critical radius ratio corre- lated to shift of transition temperature. The bulk electrical capaci- tance of PbTiO 3 originates from its grain boundaries [6]. Properties of polycrystalline electro ceramic materials are highly dependent on micro-structure and the grain boundary properties may be significantly differ from each other. Also, it is often observed that the electrical response from a material is not an intrinsic and it is dominated by many extrinsic factors like grain boundary, surface layers and electrodeematerial interface etc [7]. The gas sensitivity and selectivity response proved by ternary transition metal oxides (CrTiO 3 ), due to its variation of resistance to reactive gases. Hence, to increase the range of selectivity of these sensors for desired gas is achieved by doping suitable ions in the host material at an elevated temperature [8]. High permittivity ceramics have been traditionally used to fabricate high voltage capacitors due to their high break down voltage. However, they suffer poor mechanical strength and therefore it is neither be exposed to high electrical fields nor effectively minimized size. Modern research in thin films of metal oxide Al 2 O 3 (Aluminum Oxide) may provide high dielectric strength and permittivity. Furthermore, technology has to be developed for producing such materials at controlled thickness of capacitors for commercial applications. Hence, an intermediate approach taken in to account for the synthesis of composite material, which combines the superior mechanical, break down and fabrication properties of polymer with excellent thermal and dielectric properties of ceramic. A composite material would thus be formed by introducing the fine powder of ceramics in to the matrix of suitable polymer. Based on the novel properties of PbTiO 3 Ferro-ceramic, it was doped by varying percentage weight with polymer PVA and composite films were synthesized. Polymer PVA is having unique chemical and physical properties [9,10]. The effect of molecular weight (MW) on dielectric properties of PVA films was reported with very interesting experimental conditions. The report highlight varying molecular weight induced polarization process is * Corresponding author. Tel.: þ91 9894566487 (mobile). E-mail address: girish.joshi@vit.ac.in (G.M. Joshi). Contents lists available at ScienceDirect Current Applied Physics journal homepage: www.elsevier.com/locate/cap 1567-1739/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.cap.2011.03.068 Current Applied Physics 11 (2011) 1322e1325