Investigation of temperature and frequency dependence of the dielectric properties of multiferroic (La0.8Ca0.2)0.4Bi0.6FeO3 nanoparticles for energy storage application

Amira Bougoffa; E M Benali; A Benali; M Bejar; E Dhahri; M P F Graça; M A Valente; G Otero-Irurueta; B F O Costa

doi:10.1039/d1ra08975g

Investigation of temperature and frequency dependence of the dielectric properties of multiferroic (La_0.8Ca_0.2)_0.4Bi_0.6FeO₃ nanoparticles for energy storage application

RSC Adv. 2022 Mar 1;12(11):6907-6917. doi: 10.1039/d1ra08975g. eCollection 2022 Feb 22.

Authors

Amira Bougoffa¹, E M Benali^{1

2}, A Benali^{1

3

2}, M Bejar¹, E Dhahri¹, M P F Graça³, M A Valente³, G Otero-Irurueta⁴, B F O Costa²

Affiliations

¹ Laboratory of Applied Physics, Faculty of Sciences of Sfax, University of Sfax B. P. 1171 Sfax 3000 Tunisia amirabougoffa@gmail.com +216 26 923 772.
² University of Coimbra, CFisUC, Physics Department Rua Larga P-3004-516 Coimbra Portugal.
³ I3N, Physics Department, University of Aveiro Campus de Santiago Aveiro Portugal.
⁴ Centre for Mechanical Technology& Automation (TEMA), University of Aveiro 3810-193 Aveiro Portugal.

Abstract

In this work we synthesized the multifunctional (La_0.8Ca_0.2)_0.4Bi_0.6FeO₃ material using a sol-gel process. Structural and morphologic investigations reveal a Pnma perovskite structure at room temperature with spherical and polygonal nanoparticles. A detailed study of the temperature dependence of the dielectric and electrical properties of the studied material proves a typical FE-PE transition with a colossal value of real permittivity at 350 K that allows the use of this material in energy storage devices. Thus, the investigation of the frequency dependence of the ac conductivity proves a correlated barrier hopping (CBH) conduction mechanism to be dominant in the temperature ranges of 150-170 K; the two observed Jonscher's power law exponents, s ₁ and s ₂ between 180 K and 270 K correspond to the observed dispersions in the ac conductivity spectra in this temperature region, unlike in the temperature range of 250-320 K, the small polaron tunnel (NSPT) was considered the appropriate conduction model.