Structural e Electrical property correlation in defect induced nanostructured off-stoichiometric bismuth ferrite: A defect analysis R.K. Dwivedi a , Pardeep K. Jha a, * , Priyanka A. Jha a, b , Pawan Kumar c, d a Department of Physics and Material Science & Engineering, Jaypee Institute of InformationTechnology, Noida, U. P. 201307, India b Department of Applied Sciences, HMR Institute of Technology and Management, GGSIPU, New Delhi 110036, India c School of Basic and Applied Sciences, K. R. Mangalam University, Sohna Road, Gurgaon, Haryana 122103, India d Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India highlights  Dielectric analysis has been carried out to analyse the defect mechanism.  RBS and EdX study confirm the elemental constituents.  Correlation between observed J-V-f behaviour and defects has been established.  HRTEM, SAED pattern and impedance analysis supports the defect analysis. article info Article history: Received 24 November 2014 Received in revised form 7 August 2015 Accepted 9 August 2015 Available online xxx Keywords: Magnetic materials Electronic microscopy Electrical characterisation Diffusion abstract In order to increase magnetization, an attempt has been made to synthesize nanostructured bismuth ferrite using high energy planetary ball milling (HEPBM). In this process local heating in HEPBM and Bi- volatility has eventually led to the formation of BiFe 5 O 12 (off stoichiometric bismuth iron garnet (BIG)). Electrical characterization has been done in order to identify the nature of defects and diffusion mechanism which has been supported by high resolution transmission electron microscopy and selected area electron diffraction images. The simultaneous analysis of current density-applied voltage (JeV) and current density-frequency (Jen) curves gives insight mechanism for defect formation and how surface charge density depends on relaxation time and frequency of field applied. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Polycrystalline ceramics particularly oxides contain large num- ber of defects, their structure and chemistry are governed by ki- netics of defect movements. These defects can be charged or neutral and can be classified into various categories such as va- cancies, interstitials and defect clusters etc. In ceramics, defect as- sociates are very important because of columbian interactions which may be strong as well as long range. In addition to this, non stoichiometry increases the concentration of defects. Various properties of oxides are dependent on the concentration of defects present in the sample. Bismuth ferrite is one of such materials in which stoichiometric problem exists due to Bi volatilization and it makes an impact on electrical and magnetic properties. In order to increase magnetization, an attempt has been made to synthesize nanostructured bismuth ferrite using high energy planetary ball milling (HEPBM). In this process local heating in HEPBM and Bi-volatility has eventually led to the formation of Bi 3d Fe 5 O 12 (off stoichiometric bismuth iron garnet (BIG)). Garnets have been mostly studied for their magnetic and magneto-optical properties [1]. There have been far fewer studies on the dielec- tric/electrical properties of bismuth iron garnet or other garnets [2]. In a few recent reports, giant increase in dielectric permittivity with temperature has been reported showing the potential for new ap- plications [3]. Effect of milling and milling duration on sintered sample and thermodynamics of phase transition are reported elsewhere [4,5]. In this work, effect of sintering on the microstructure and structural imperfections for 40 h milled (N40) sample has been studied in detail. The electrical conductivity depends on the type, * Corresponding author. E-mail address: pardeepjha.jiit@gmail.com (P.K. Jha). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys http://dx.doi.org/10.1016/j.matchemphys.2015.08.012 0254-0584/© 2015 Elsevier B.V. All rights reserved. Materials Chemistry and Physics xxx (2015) 1e8 Please cite this article in press as: R.K. Dwivedi, et al., Structural e Electrical property correlation in defect induced nanostructured off- stoichiometric bismuth ferrite: A defect analysis, Materials Chemistry and Physics (2015), http://dx.doi.org/10.1016/j.matchemphys.2015.08.012