Magnetic, dielectric and electrical modulus of Ce3+ doped cobalt–magnesium ferrite nanoparticles

Abstract

In this work, the magnetic, dielectric properties and electric modulus of Ce3+ substituted cobalt-magnesium (Co0.7Mg0.3CexFe2–xO4) (labeled as CMCF) ferrite nanoparticles were investigated in detail. Saturation magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce3+ ions. Meanwhile, coercivity increases from 738.22 Gs for the CMCF0 sample to 912.10 Gs for the CMCF2 sample, then decreases monotonically to 762.1 Gs for the CMCF5 sample. The cerium content and particle size play important roles in controlling the magnetization and coercivity of the CMCF nanoparticles. All CMCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 GHz. The CMCF nanoferrites' dielectric parameter dispersion exhibits normal behavior. The pristine Co–Mg nanoferrite only has ε′ value of 28.25, but the nanoferrite MCMF2 has ε′ value of 365.03, with an enhancing ratio of 1192%. The conduction mechanism of the MCMF nanoferrites was determined by fitting the σac results via the Jonscher power law. At 653 K, large polaron tunnelling is thought to be responsible for this conduction process, which is followed by electron barrier hopping at higher temperatures. Cole–Cole diagrams at different temperatures, assuring the contributions of the grains and their boundaries at lower temperatures (653 K) and only the grains at higher temperatures. Based on our results, the CMCF nanoferrites hold magnetic and semiconducting nature, which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.