| Effects of hafnium on the structural, optical and ferroelectric properties of sol–gel synthesized barium titanate ceramics |
| Jude Fernandez1, B. Bindhu1, M. Prabu2, K. Y. Sandhya3 |
1Department of Physics, Noorul Islam Centre for Higher Education, Kumaracoil, Thuckalay, Kanyakumari District, Tamil Nadu 629180, India
2Department of Nanotechnology , Noorul Islam Centre for Higher Education , Kumaracoil, Thuckalay , Kanyakumari District , Tamil Nadu 629180 , India
3Department of Chemistry , Indian Institute of Space Science and Technology , Thiruvananthapuram , Kerala 695547 , India |
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Received: August 5, 2021; Revised: October 20, 2021 Accepted: November 23, 2021. Published online: March 31, 2022. |
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| ABSTRACT |
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For future electronic devices, barium titanate based multifunctional ceramics falling under the category of ABO3 perovskite type rose to prominence among scientists and engineers around the world. Moreover, the remarkable properties can be tuned by a strategy known as doping. The synthesis of hafnium (Hf4+) doped BaHfxTi(1- x)O3, x = 0.00, 0.05, 0.10, 0.15 ceramics based on a wet chemical technique known as sol–gel, where the total time and temperature required for complete phase formation is considerably less, is reported in this article. The formation of a well-defined crystal structure with tetragonal phase showing P4mm space group was confirmed for BaHfxTi(1- x)O3 ceramics calcined at 1000 °C using Raman spectroscopy and X-ray diffraction (XRD). The calcined powders consisting of grains with polyhedral shapes possessed particle sizes ranging from 160 to 460 nm. A significant peak corresponding to metal oxide formation was obtained at 565 cm−1 for all the compositions in Fourier transform infrared (FTIR) spectra, proving the existence of the required perovskite phase. A minor variation in band gap energy with increase in Hafnium (Hf4+) was found out using Ultraviolet–Visible-near-IR (UV–Visible-NIR) spectroscopy. Photoluminescence (PL) spectrum analysis, put forward the possibility of slight disorders in the ceramics; nonetheless, the spectra were found to be composed of peaks corresponding to blue, red and green emissions. The remnant polarization (Pr), saturation polarization (Ps) and coercive electric field (Ec) of BaHfxTi(1- x)O3, calculated from ferroelectric hysteresis loop were found to vary appreciably with corresponding rise in hafnium (Hf4+) concentration. |
| Key words:
Hafnium doped barium titanate · Sol–gel · Ferroelectric · Band-gap energy · Raman spectroscopy · Polarization |
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