Effect of heating rate on microstructure and electrical properties of microwave sintered CaCu3Ti4O12 ceramics

Sandeep Kumar1, Neetu  Ahlawat1*, Navneet Ahlawat2

1Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar, Haryana 125001, India

2Matu Ram Institute of Engineering and Management, Rohtak, Haryana 124001, India

Adv. Mater. Lett., 2017, 8 (5), pp 605-613

DOI: 10.5185/amlett.2017.6398

Publication Date (Web): Apr 04, 2017

E-mail: neetugju@yahoo.co.in

Abstract


In the present work, the results of microstructure, dielectric and ferroelectric investigation of microwave sintered CaCu3Ti4O12 (CCTO) ceramic with different heating rate are presented. Scanning electron micrographs revealed that grain size decreases from 1.167 µm to 0.744 µm with increased heating rate from 10ºC/min. to 50ºC/min which can be explained on the basis of phenomenological kinetic equation for grain growth. Dielectric response also found to influence by heating rate. The CCTO ceramic sintered with 50 ºC/min. exhibited highest dielectric constant (ɛr~3915) with nominal losses (0.10) at room temperature in broad frequency range from 102Hz-105Hz. Cole-Cole plots revealed the change in grain boundary resistivity mainly caused by the oxygen vacancy activities and affected by varying sintering heating rate. An anomaly observed for 50 ºC/min heating rate due to trapping of oxygen at grain boundaries. The remnant polarization and coercive field for CCTO ceramic sintered with 50ºC/min were 0.1 µC /cm2 and 1.477 kV /cm respectively. Remnant polarization found to decrease while the coercive field increases with increasing heating rate applying these are micro-structural dependent.    

Keywords

CaCu3Ti4O12, dielectric, ferroelectric, P-E loop, microwave, heating rate.

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