Structural, dielectric, and magnetic properties of Dy-substituted BiFeO 3 multiferroic ceramics

The effect of Dy 3+ ion substitution on structural, dielectric, and magnetic behavior of BiFeO 3 ceramics has been studied which was prepared via the solid-state route. Structural analysis reveals that the replacement of the Dy 3+ ion with that of Bi 3+ results in a phase transformation from rhombohedral ( x = 0.05) to mixed orthorhombic and rhombohedral ( x = 0.10, 0.15, 0 . 20) along with a reduction in crystallite size. At 463 K, the anomalous behavior in dielectric constant was observed, which indicates high temperature transient interaction between oxygen vacancies and the Fe 3+ /Fe 2+ ions. The complex nonlinear Cole–Cole fitted plots in impedance study revealed the presence of grains with finite grain boundaries, and electrode effects. All the prepared ceramic samples have been found to exhibit electric relaxation of non-Debye type with a negative (− ve) temperature coefficient of resistance, analogous to a semiconductor behavior. The observation of M-H loops shows the magnetic properties at room temperature which indicates that increasing the Dy substitution results in an effective modification of the spiral spin structure of BiFeO 3 , leading to improved net magnetization. The maximum values of remanent magnetization ( M r = 0.065573 emu/g) and coercive field ( H c = 170.66 Oe) were obtained for the sample x = 0.20. Hence, the addition of the rare earth element Dy improves the magnetic and dielectric properties of pure BiFeO3, making it a suitable choice for data storage media.