Study of the influence of 2.5% Mg2+ insertion in the B-site of La0.8Ca0.1Pb0.1FeO3 on its structural, electrical and dielectric properties

H Issaoui; A Benali; F Issaoui; E Dhahri; B F O Costa; M P F Graca; M A Valente; Mohamed Lamjed Bouazizi

doi:10.1039/d1ra04041c

Study of the influence of 2.5% Mg²⁺ insertion in the B-site of La_0.8Ca_0.1Pb_0.1FeO₃ on its structural, electrical and dielectric properties

RSC Adv. 2021 Oct 7;11(52):33070-33080. doi: 10.1039/d1ra04041c. eCollection 2021 Oct 4.

Authors

H Issaoui^{1

2}, A Benali^{2

3}, F Issaoui⁴, E Dhahri², B F O Costa¹, M P F Graca³, M A Valente³, Mohamed Lamjed Bouazizi⁵

Affiliations

¹ University of Coimbra, CFisUC, Physics Department P-3004-516 Coimbra Portugal.
² Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax B.P. 1171 3000 Sfax Tunisia.
³ I3N and Physics Department, University of Aveiro 3810-193 Aveiro Portugal.
⁴ Research Unit Valorization and Optimization of Resource Exploitation, Faculty of Science and Technology of Sidi Bouzid, University of Kairouan Sidi Bouzid 9100 Tunisia.
⁵ College of Engineering, Prince Sattam Bin Abdulaziz University 655 Al Kharj 11942 Saudi Arabia.

Abstract

This work involves the synthesis and study of physical properties of the La_0.8Ca_0.1Pb_0.1Fe_0.975Mg_0.025O₃ compound, which has been characterized by various experimental techniques, such as X-ray diffraction, SEM and complex impedance spectroscopy. The structural study showed that the La_0.8Ca_0.1Pb_0.1Fe_0.975Mg_0.025O₃ compound crystallized in the orthorhombic structure with the Pnma space group. The particle size and the surface morphology of this compound have been analysed using SEM. The particle size was found to be around 120 nm and we confirmed that one particle contains more than one crystallite. Importantly, the studied compound presented a giant dielectric permittivity (ε' of around 9 × 10⁴ at high temperature and low frequencies). An equivalent electric circuit has been deduced from the Nyquist plots of the complex impedance parts (Z'' vs. Z') to correctly describe the electrical behavior of the La_0.8Ca_0.1Pb_0.1Fe_0.975Mg_0.025O₃ compound. The chosen circuit consists of two cells mounted in series corresponding to the grain and grain boundary contributions. The electrode contribution has been detected from the frequency dependence of the imaginary part of modulus where the activation energy of each constitution has been calculated. The relaxation process and the electrical conductivity are attributed to the same type of charge carriers characterized by similar values of the activation energy determined from loss factor tangent (tg(δ)), the imaginary part of the permittivity and the modulus spectrum.