Materials Chemistry and Physics 258 (2021) 123921 Available online 26 October 2020 0254-0584/© 2020 Elsevier B.V. All rights reserved. Effects of synthesis and sintering temperature in BCT-BST ceramics C. Pavithra a , W. Madhuri b, * , S. Roopas Kiran c a Department of Physics, Marudhar Kesari Jain College for Women, Vaniyambadi, Tamilnadu, India b Ceramic Composites Laboratory, CCG, VIT, Vellore, Tamilnadu, 632014, India c Department of Physics, VIT, Amarvathi, Andhra Pradesh, India HIGHLIGHTS • 0.55(Ba 0⋅9 Ca 0.1 )TiO 3 -0.45Ba(Sn 0⋅2 Ti 0.8 )O 3 (BCT-BST) is prepared by three different methods. • Densifcation temperature varies between 1250 ◦ C and 1400 ◦ C depending on the synthesis technique. • The high dielectric constant is achieved around 18 K. • The phase transition is noticed around 71 ◦ C at all the preparation methods. • BCT-BST is a soft ferroelectric material. A R T I C L E INFO Keywords: BCT-BST Solid state method A sol-gel method Molten-salt method High dielectric constant ABSTRACT Morphology and properties of ceramics are frst attributes of synthesis techniques and sitering temperature. In order to understand the effect of synthesis techniques and sintering temperature 0.55(Ba 0⋅9 Ca 0.1 )TiO 3 -0.45Ba (Sn 0⋅2 Ti 0.8 )O 3 (BCT-BST) is synthesized by solid state reaction (SSR), sol-gel method and molten-salt methods. The cubic crystal structure of all the synthesized BCT-BST is confrmed by X-ray powder diffraction analysis. Densifcation temperature varies between 1250 ◦ C and 1400 ◦ C depending on the synthesis technique. The morphology and particle size of each of BCT-BST is studied using scanning electron microscope. Particle size is found to be in the range of 32 nm–60 nm. Dielectric studies on each of BCT-BST are carried out as a function of temperature and frequency. The morphotropic phase boundary is noticed at 71 ◦ C and a high dielectric constant of 18,000 noticed for sol gel synthesized BCT-BST. A soft ferroelectric hysteresis curve is exhibited by each of BCT-BST. 1. Introduction Ferroelectric ceramics have wide range of applications in the elec- tronics industry because of its high dielectric constant, piezoelectric and ferroelectric property [1,2]. Of all lead based ceramics especially PZT offer excellent dielectric and ferroelectric as well as piezoelectric properties best suited for various applications. Lead-based materials fnd their place in the electronic and microelectronicdevices such as non-volatile memory devices, sensors, capacitors, actuators, microelec- tronic mechanical systems (MEMS) etc. However, such lead-based ma- terials face high volatilization and pose environmental hazards, due to toxic nature of lead. In the given scenario there is an urgent need to develop lead-free materials with colossal dielectric constant and giant d33 [3,4]. Barium titanate offers good dielectric and ferroelectric properties and is environment friendly. With high dielectric constant and ferro/piezoelectric coeffcient barium titanate (BT) is a potential candidate that can replace PZT. Further improvement in BT is desirable and the contemporary research is stirring in the direction [5]. The basic ways to improve ferroelectric properties is to decrease the grain size so as to increase surface to volume ratio. Large grain surface favours large local felds resulting in improved dielectric constant. Another way is at phase boundary points, at these points dipoles are unstable and align in the applied direction resulting in high dielectric constant [5–7]. The method of phase boundary modifcation is done by partial replacement of barium in the ceramics. On rigorous literature survey [8] it is noticed that BCT-BST ceramic is reported to exhibit giant dielectric constant and very high d33 coeffcient. Further the properties of ceramic depends on the method of synthesis and the temperature it is sintered. Adopting a * Corresponding author. E-mail address: madhuriw12@gmail.com (W. Madhuri). Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys https://doi.org/10.1016/j.matchemphys.2020.123921 Received 20 August 2020; Received in revised form 5 October 2020; Accepted 11 October 2020