Author(s)

Sajal Chandra Mazumdar¹, Sanjib Datta¹, Farhad Alam²

¹Department of Physics, Comilla University, Cumilla, Bangladesh.
²Department of Physical Sciences, Independent University, Bangladesh, Dhaka-1229, Bangladesh.

The novel polycrystalline Bi_0.85Gd_0.15Cu_xFe_1-xO₃ (x = 0, 0.025, 0.05, 0.075, 0.10) multiferroics are synthesized by the usual solid-state reaction route. The synthesis of the desired phase has been verified by the X-ray Diffraction (XRD) patterns. With major structural phases, few traces of secondary phases of Bi₂Fe₄O₉ and Bi₂₅FeO₄₀ appear for all the compositions. A discontinuous series of structural changes with varying compositions are observed for the doped samples. The bulk density (ρ_B) increases with Cu content reaches the highest at x = 0.05 and then declines. The complex initial permeability and dielectric characterizations are performed by Wayne Kerr Impedance Analyzer. The x = 0.05 samples having maximum density exhibit the highest permeability (μ_i’) implying a close relation between μ_i’ and the density. The reduction of μ_i’ at higher Cu concentration is due to the low density of the samples associated with the increased intragranular pores. The dielectric constant (ε’) is measured against frequency in the range 1 kHz - 10 MHz. It is perceived that ε’ falls with the rise in frequency up to 100 kHz. This dielectric dispersion is observed at a lower frequency as a result of interfacial polarization outlined by Maxwell-Wagner. The maximum ε’ is obtained for x = 0.025 composition. In the low-frequency range, the AC conductivity σ_AC is practically independent of frequency and resembles the DC conductivity (σ_DC). In the vicinity of high frequency recognized as the hopping region, σ_AC rises since the conductive grains are more active at high frequencies. The co-doping with Gd and Cu in BiFeO₃ ceramics enhances the magnetic and dielectric properties of the ceramics and hence can be utilized for fabricating multifunctional devices.

X-Ray Diffraction, Permeability, Dielectric Constant, Conductivity

Mazumdar, S. , Datta, S. and Alam, F. (2022) Structural, Magnetic and Transport Properties of Gd and Cu Co-Doped BiFeO₃ Multiferroics. Journal of Applied Mathematics and Physics, 10, 2026-2039. doi: 10.4236/jamp.2022.106138.