Improved conductivity and reduced dielectric loss of Cu- substituted NiFe2O4 for high frequency applications

• Published in: Journal of alloys and compounds 2020-10, Vol.839, p.155601, Article 155601
• Main Authors: Chouaibi, H., Khelifi, J., Benali, A., Dhahri, E., Valente, M.A., koumina, A.
• Format: Article
• Language: English
• Subjects: Ac conductivity; Copper; Current carriers; Dielectric loss; Dielectric relaxation; Electrical resistivity; Ferromagnetic materials; High frequencies; Impedance spectroscopy; Magnetic measurement; Nickel ferrites; Relaxor behavior; Relaxors; Sol-gel; Sol-gel processes; Spinel ferrite; Substitution reactions
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.155601

To promote suitable materials to be helpful for the electrical devices at high frequency application, we elaborated Cu substituted NiFe2O4 [NiFeCuO4 (NFCO)] by sol-gel reaction route and investigated the effect of Cu2+ on various properties of nanocrystalline NiFe2O4. The formation of pure cubic phase spinel NFCO was confirmed through X-ray diffraction (XRD). Magnetic measurement reveals the ferromagnetic behavior of the material. Exploring of ac conductivity grounded on Jonsher’s power law proves that the conduction is related to the Correlated Barrier Hopping (CBH) model. Our compound exhibits the Relaxor character. Electrical modulus study unveils the presence of the non-Debye type of dielectric relaxation. Activation energies calculated from the conductivity pattern, impedance and Modulus prove to be close, which confirms that the relaxation process and the electrical conductivity may be attributed to the same type of charge carriers. The substitution of Fe by Cu in NiFe2O4 increases the ac conductivity and reduces the dielectric loss compared to NiFe2O4. The semiconductor behavior and the lower values of dielectric loss illustrate that Cu- substituted NiFe2O4 display potential applications for integrated electronic chips, microwave and electrical devices at high frequency. [Display omitted] •Electrical modulus study unveils the presence of the non-Debye type of dielectric relaxation.•Activation energies calculated from the conductivity pattern, impedance and Modulus prove to be close, which confirms that the relaxation process and the electrical conductivity may be attributed to the same type of charge carriers.•The substitution of Fe by Cu in NiFe2O4 increases the ac conductivity and reduces the dielectric loss compared to NiFe2O4.