Structural, dielectric, and impedance properties of BiFeO3-GdFeO3 ceramics

The 0.8BiFeO3-0.2GdFeO3 (BFO-GFO) relaxor ferroelectric ceramics were synthesized by solid-state reaction method. Rietveld refinement revealed the co-existence of rhombohedral structure (space group, R3c) and orthorhombic phase (space group, Pn21a). High theoretical relative density (∼98%), significant ferroelectricity (Ps = 4.2 μC/cm2, Pr = 1.8 μC/cm2) and high Currie temperature (522 K−663 K) are measured. High diffuseness behavior with ΔTm = 112 K, γ = ∼1.7–1.9, and full width half maximum of TFWHM = 200 K, reveal excellent relaxor ferroelectric of ceramics. Correlated barrier hopping model (CBH) was used to explain the characteristic of conductivity by fitting the density of stats near Fermi level. Impedance spectrum analysis and the calculated activation energy revealed the ionization of oxygen vacancies contributes the conductance of grains and grain boundaries, respectively. [Display omitted] •Relaxor ferroelectric ceramics of BFO-GFO are synthesized.•Rhombohedral structure and orthorhombic phase coexist in BFO-GFO ceramics.•High theoretical relative density, significant ferroelectricity and high Currie temperature are measured.•BFO-GFO ceramics possess high diffuseness behavior with ΔTm = 112 K, γ = ∼ 1.7–1.9, and TFWHM = 200 K.•Multiple models and fitting methods are used to analyze the mechanism of conductivity.