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Barium strontium titanate (Ba0.8Sr0.2TiO3, BST) nanocrystalline ceramics have been synthesized by high energy ball milling. As the sintering temperature increases from 1200 ℃ to 1350 ℃, the average grain size of BST ceramics increases from 86 nm to 123 nm. The X-ray diffraction (XRD) studies show that these ceramics are tetragonal. The phase and grain size of the sintered pellets have been estimated from the XRD patterns, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The effect of grain size on dielectric and ferroelectric properties is studied. The dielectric and piezoelectric parameters are greatly improved at room temperature with increase in grain size. The Curie transition temperature is found to shift slightly towards higher temperatures as the grain increases from 86 nm to 123 nm. The coercive field decreases and the remnant polarization and spontaneous polarization increase as the grain size of BST nano ceramics increases. These ceramics are promising materials for tunable capacitor device applications.


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Effect of grain size on dielectric and ferroelectric properties of nanostructured Ba0.8Sr0.2TiO3 ceramics

Show Author's information Venkata Ramana MUDINEPALLIa( )Leng FENGbWen-Chin LINaB. S. MURTYc
Department of Physics, “National Taiwan Normal University”, Taipei 11677, Taiwan, China
Department of Chemistry, Shenzhen Graduate School, Peking University, Shenzhen 518055, China
Nanotechnology Laboratory, Department of Metallurgical and Materials Engineering, Indian Institute of Technology-Madras, Chennai 600036, India

Abstract

Barium strontium titanate (Ba0.8Sr0.2TiO3, BST) nanocrystalline ceramics have been synthesized by high energy ball milling. As the sintering temperature increases from 1200 ℃ to 1350 ℃, the average grain size of BST ceramics increases from 86 nm to 123 nm. The X-ray diffraction (XRD) studies show that these ceramics are tetragonal. The phase and grain size of the sintered pellets have been estimated from the XRD patterns, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The effect of grain size on dielectric and ferroelectric properties is studied. The dielectric and piezoelectric parameters are greatly improved at room temperature with increase in grain size. The Curie transition temperature is found to shift slightly towards higher temperatures as the grain increases from 86 nm to 123 nm. The coercive field decreases and the remnant polarization and spontaneous polarization increase as the grain size of BST nano ceramics increases. These ceramics are promising materials for tunable capacitor device applications.

Keywords:

nanocrystalline ceramics, lead free ceramics, crystallization, electron microscopy, dielectric properties, hysteresis
Received: 10 August 2014 Revised: 14 September 2014 Accepted: 22 September 2014 Published: 31 January 2015 Issue date: March 2015
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Publication history

Received: 10 August 2014
Revised: 14 September 2014
Accepted: 22 September 2014
Published: 31 January 2015
Issue date: March 2015

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© The author(s) 2015

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