La³⁺ substitution impact on structural, magnetic, and electrical properties of CoFe₂O₄ synthesized via sucrose auto-combustion

Abstract Lanthanum (La)-substituted cobalt ferrites CoFe 2- x La O 4 ( = 0.00–0.09) were successfully prepared using the sucrose sol-gel auto-combustion route. La-substitution effects on structural, magnetic, and electrical/dielectric characteristics investigated different techniques. X-ray diffraction (XRD) results displayed a deviation from single-phase structure at La-content ? 0.04 because of formation orthorhombic LaFeO 3 boundaries grains. Both XRD Fourier transform infrared (FT-IR) measurements showed that crystal had not been significantly affected by attributed to crystallization out this . Vibrating sample magnetometry (VSM) revealed gradual decreases in magnetization as increases, which could be referred decrease super-exchange interaction octahedral sites preferential substitution large ionic radius 3+ ions positions. As antiferromagnetic formed, severe reduction appeared. The increase 0.09 was cationic redistribution among sublattices. On other hand, coercivity data indicated hard magnetic all samples. electrical conductivity semiconducting character samples with obvious increasing La-content. According Verwey’s hopping mechanism, these occupation Dielectric versus temperature anomalies relaxations around 460 K successive addition lanthanum inhomogeneity occurred due oxygen vacancy created or Maxwell-Wagner mechanism.