Effect of Co substitution on the structural, electrical, and magnetic properties of Bi_0.9La_0.1FeO₃ by sol-gel synthesis

Cobalt (Co)-doped Bi_0.9La_0.1FeO₃ multiferroics were synthesized by a sol-gel method based on the autocombustion technique. As-synthesized powder was examined using various characterization techniques to explore the effect of Co substitution on the properties of Bi_0.9La_0.1FeO₃. X-ray diffraction reveals that Co-doped Bi_0.9La_0.1FeO₃ preserves the perovskite-type rhombohedral structure of BiFeO3, and the composition without Co preserves the original structure of the phase; however, a second-phase Bi2Fe4O9 has been identified in all other compositions. Surface morphological studies were performed by scanning electron microscopy. Temperature-dependent resistivity of the samples reveals the characteristic insulating behavior of the multiferroic material. The resistivity is found to decrease with the increase both in temperature and Co content. Room temperature frequency-dependent dielectric measurements were also reported. Magnetic measurements show the enhancement in magnetization with the increase in Co content.