| Effect of La substitution on the structural, optical, ferroelectric, and electrical properties of BiFeO3 |
K. Krishna Rao1, T. Durga Rao1
, V. Sudharshan2, B. Sattibabu1, T. Karthik3, K. Lakshun Naidu1, S. Bharadwaj4, Md. Halima1 |
1Department of Physics, School of Science, GITAM (Deemed to Be University), Visakhapatnam, Andhra Pradesh, 530045, India
2Department of Physics, VIT-AP University, Amaravati, Andhra Pradesh, 522237, India
3Centre for Materials for Electronics Technology [C-MET], Ministry of Electronics and Information Technology (MeitY), Thrissur, Kerala, 680581, India
4Department of Physics, School of Science, GITAM (Deemed to Be University), Hyderabad, Telangana, 502329, India |
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Received: November 20, 2024; Revised: April 7, 2025 Accepted: April 28, 2025. Published online: May 17, 2025. |
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| ABSTRACT |
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Bi1-xLaxFeO3 (x = 0.00–0.50) compounds were made and their structural, ferroelectric, optical and impedance characteristics were investigated. Structural analysis using Rietveld refinement revealed that structure with an orthorhombic Pnma space group was emerged at the expense of rhombohedral R3c structure with increasing La content. UV–visible spectroscopy measurements showed an increase in the optical band gap between 2.03 and 2.18 eV when x changes from 0 to 0.50. The Fourier transform infrared radiation measurements showed two prominent absorption bands that were seen at about 435 and 535 cm-1, which corresponded to the bending and stretching vibrations of the Fe–O bonds in the FeO6 octahedral unit, respectively. The polarization measurements demonstrated that ferroelectric properties were enhanced for the x = 0.10 compound but declined for higher values of x. The impedance measurements evidenced improved insulating character with the La substitution. The grain and grain resistance of the compounds were extracted using two parallel RC circuit models. The impedance measurements revealed that the compounds displayed a negative temperature coefficient of resistance character. The ac conductivity studies indicated that the conductivity of the substituted compounds reduced with the substitution. |
| Key words:
Crystal structure · Optical properties · Infrared (IR) spectroscopy · Ferroelectric · Electrical properties · Grain size |
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