Enhanced magnetization and improved insulating character in Eu substituted BiFeO3

Abstract

The polycrystalline Bi1−xEuxFeO3 (x = 0, 0.05, and 0.1) ceramics were synthesized by conventional solid-state route. X-ray diffraction studies and Raman measurements revealed that the compounds crystallized in rhombohedral structure with R3c space group. In addition, a nominal percentage of orthorhombic phase was observed in 10 mol. % Eu substituted BiFeO3. Appearance of weak ferromagnetism and significant increase in Néel temperature TN in the substituted compounds were discussed on the basis of structural distortions. Enhanced remnant magnetization of 75 memu/g and large coercive field of 6.4 kÖe were observed in 10 mol. % Eu substituted BiFeO3. Equivalent circuit model was employed to estimate the grain and grain boundary contributions towards the electrical parameters such as resistance and conductivity. Non-Debye type of relaxation was confirmed from impedance and electric modulus studies. The obtained frequency variation of ac conductivity at different temperature obeys Jonscher's power law and is consistent with the correlated barrier hopping model. Temperature variations of ac conductivity explained that electronic hopping, oxygen vacancies movement, and/or creation of defects contribute to conduction in all the compounds.