Effect of Sm, Co codoping on the dielectric and magnetoelectric properties of BiFeO3 polycrystalline ceramics

• Published in: Journal of magnetism and magnetic materials Vol. 324; no. 13; pp. 2121 - 2126
• Main Authors: Song, G.L., Zhang, H.X., Wang, T.X., Yang, H.G, Chang, F.G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-07-2012; Elsevier
• Subjects: Ceramics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Crystal defects; Dielectric; Dielectric constant; Dielectric loss and relaxation; Dielectric properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Ferroelectric materials; Magnetic fields; Magnetic properties; Magnetic properties and materials; Magnetism; Magnetoelectric; Magnetomechanical and magnetoelectric effects, magnetostriction; Multiferroic; Permittivity (dielectric function); Physics; Space charge; Space charge; Dielectric; Multiferroic; Magnetoelectric; Crystal defects; Space-charge-limited conduction; Polycrystals; Bismuth Iron Oxides Mixed; Liquid phase sintering; Ferroic material; Samarium additions; Magnetoelectric effects; Dielectric losses; Cobalt additions; Permittivity; Codoping; Exchange interactions
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2012.02.024

Multiferroic Bi0.95Sm0.05Fe1−xCoxO3 (x=0−0.1) ceramics were prepared by the rapid liquid phase sintering method. For all the samples studied, the dielectric constant and dielectric loss decrease with increasing frequency in the range from 1kHz to 1MHz. It shows that the dielectric constant of Bi0.95Sm0.05FeO3 at 10kHz is about forty times larger than that of pure BiFeO3. This dramatic change in the dielectric properties of Bi0.95Sm0.05Fe1−xCoxO3 (x=0−0.1) samples can be understood in terms of the space charge limited conduction associated with crystal defects, which was indicated by the increase of magnetoelectric effect with doping Co3+ under applied magnetic field from 1 to 8kOe. It was believed that the ferroelectric polarization enhancement comes from the exchange interaction between the Sm3+ and Fe3+ or Co3+ ions for Bi0.95Sm0.05Fe0.95Co0.05O3 at room temperature.
► Sm and Co dopants significantly decreased the grain sizes of BFO ceramics from the SEM images. ► The dielectric constant of Bi0.95Sm0.05FeO3 measured at 10kHz was about forty times larger than that of pure BiFeO3. ► The values of ME effect of Bi0.95Sm0.05Fe1−xCoxO3 samples can be enhanced by doping Sm3+and Co3+. ► Maximum ME effect as high as 4.2% observed at x=0.05 (Bi0.95Sm0.05Fe0.95Co0.05O3).