Synthesis, characterization, and dielectric properties of nanocrystalline Ba 1−x Pb x ZrO 3 (0 ≤ x ≤ 0.75) by polymeric

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Mohd Ubaidullah and Sarvari Khatoon Department of Chemistry, Nanochemistry Laboratory, Jamia Millia Islamia, New Delhi 110025, India

Jamal H. Madani Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia

Tokeer Ahmadb) Department of Chemistry, Nanochemistry Laboratory, Jamia Millia Islamia, New Delhi 110025, India (Received 23 February 2012; accepted 28 June 2012)

Solid solutions of Ba1xPbxZrO3 (0 # x # 0.75) have been synthesized successfully by polymeric citrate precursor method for the first time. The solid solutions were characterized by powder x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and surface area studies. XRD studies reveal the monophasic nature of these highly crystalline nanoparticles (except few impurity of ZrO2 in PbZrO3). Lattice parameter of Ba1xPbxZrO3 (0.20 # x # 0.75) decreases with increasing the Pb content. Dielectric properties of these nanoparticles were investigated as a function of frequency and temperature. The dielectric constant for x 5 0.15 showed a maximum value of 75.5.

I. INTRODUCTION

Perovskite oxides (general formula ABO3) have attracted the attention of researchers for their applications in electronic industry due to their unique ferroelectric (FE), pyroelectric, piezoelectric, and dielectric properties.1–8 Alkaline earth metal zirconates (BaZrO3, SrZrO3) are assumed to be potentially important materials because of their applications9–11 in multilayer ceramic capacitors, piezoelectric and pyroelectric sensors, dynamic random access memories, wireless communication devices, refractories, and heterogeneous catalysis. PbZrO3 is also an important material for energy storage devices due to the antiferroelectric (AFE) to FE phase transition.12 PbZrO3 has been extensively focused for its microwave dielectric properties but it shows dielectric relaxation near microwave frequencies.13 Barium zirconium oxide shows photoluminescence at room temperature,14 radio luminescence,15 and is a good refractory material with a high melting point (2600 °C), weak thermal conductivity, and low thermal expansion coefficient. A large number of methods have been used to prepare metal zirconates such as coprecipitation,16 alkoxide sol– gel,17 hydrothermal, solid state,9 chemical decomposition of an oxalate precursor, or combustion technique Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2012.242 J. Mater. Res., Vol. 27, No. 19, Oct 14, 2012

using oxalic hydrazide.18 Ba1xPbxZrO3 is also prepared at high Pb concentration (x $ 0.25) using reverse micellar route19; however, low concentration was not attempted by this method. These methods have several disadvantages. The alkoxide sol–gel process utilizes expensive precursors and requires careful control of the atmosphere; however, the coprecipitation method requires cations with similar solubility. Among the nonconventional wet chemical processes of obtaining oxide materials, the alkoxide sol–gel me