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(1−x)BiFeO3–(x)Pb(Fe2/3W1/3)O3 ceramics (x = 0.00–0.30) were synthesized by a solid-state reaction route. Structural characterization was done by X-ray diffraction and Raman spectroscopic studies. Existence of rhombohedral symmetry with the R 3 c space group up to x ≤ 0.20 and a transition to cubic symmetry with the P m 3 ¯ m space group for x > 0.25, confirmed with Rietveld refinement. Raman studies also confirm the significant modification at the A-site due to the replacement of Bi3+ atom by Pb2+ indicating the structural modification in Pb(Fe2/3W1/3)O3 (PFW) in BiFeO3 (BFO). Morphology and microstructure were observed using SEM micrographs and the average grain size was decreased with the increase in PFW concentration (x). Enhanced magnetic and ferroelectric properties were observed up to x ≤ 0.20, which can be attributed to the suppression of spin-canted structure and reduced leakage currents. Hence, BFO–PFW solid ceramics, with a limited low composition region, can be useful for magneto-electric device applications. [ABSTRACT FROM AUTHOR]

(Bi0.5La0.5)FeO3 Orthoferrite ceramics were prepared by a conventional solid-state reaction method on a bulk scale and on a nano range by sol–gel auto combustion and Hydrothermal methods, respectively. The phase purity and crystallinity of the prepared ceramics have been examined by X–ray diffraction study. Broadening of the maximum intensity peak (hkl) and smaller crystallite size has been noticed in both chemical methods i.e., sol–gel and hydrothermal. Rietveld refinement confirmed the presence of orthorhombic symmetry with a space group for the ceramics synthesized through all three processes. The crystallite size, particle morphology, and grain microstructure formation mechanism were correlated for prepared ceramics with FESEM and XRD results. The influence of synthesis conditions on structure, microstructure, and magnetic studies has been studied. The M-H hysteresis loop study reflects that tuning of particles or crystallite size might induce a productive enhancement in magnetization response for chemically synthesized ceramics. [ABSTRACT FROM AUTHOR]

Ho–substituted Bi4-xHoxTi2FeO12 (x = 0, 0.5, 1.0, 1.5) n = 3 Aurivillius layered perovskite compounds were prepared by a conventional solid-state reaction method. X-ray diffraction study reveals that the compounds exhibited a major orthorhombic structure with the B2cb space group. A plate-like grain with high randomness in the distribution of Ho-modified BTFO compounds was noticed in the SEM studies. T—dependent dielectric studies were performed to examine the role of defect dipole orientation and oxygen vacancies on dielectric relaxation. For x > 0.50 compositions, a decrease in Curie temperature (Tm) with the increase in Ho-substituted in BTFO ceramics was observed. A temperature-dependent AC conductivity study reveals that the ionic conductivity induced by doubly ionized oxygen vacancies is prominent in the high-temperature region. An Increase in polarization values was observed with Ho doping due to improved grain boundaries. The detailed studies on the ferroelectric (P-E) loops and magnetization (M-H) loops of Ho—substituted BTFO ceramics were determined to point out the inherent multiferroic character. The basic photoluminescence (PL) studies indicated a well noticed two distinct bands in the visible region along with a weak PL band observed in the infra-red (IR) region, which suggests the emission involves the two types of Ho3+ centers for the visible bands. [ABSTRACT FROM AUTHOR]