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The yttrium (Y)-modified bismuth ferrite (BFO) ceramic compound (i.e. Bi(Fe0.85Y0.15)O3, abbreviated as BFYO15) has been synthesized through a standard solid state reaction technique. The results of its various properties, such as structural, dielectric and electrical features of Y-modified BFO were thoroughly investigated. The analysis of X-ray diffraction data confirms the phase formation of the compound, and shows the structural change from the rhombohedral to orthorhombic crystal system. The calculated average crystallite size of the sample was found to be 42 nm. The detailed studies of the dielectric parameters, impedance and ac-conductivity were performed in a wide frequency range (1–1000 kHz) at different temperatures (25–350°C). All the studies clearly show the significant change in dielectric and other electrical parameters on Y-substitution at the Fe site. Further, some of the results and electrical characteristics of the material may be used to select the material for potential device applications. [ABSTRACT FROM AUTHOR]

The Ni- and Ti-modified BiFeO3 nanoceramic (i.e., Bi(Ni0.45Ti0.45Fe0.10)O3) with various effective ball milling times (i.e., 10 h, 20 h and 30 h) were blended by planetary (high energy) ball milling method in conjunction with a traditional solid-state reaction route. The outcome of milling time on various properties, such as structural, electrical and ferroelectric features of Ni/Ti modified BiFeO3, was investigated thoroughly. These properties were interpreted using distinct characterization tools, such as powder X-ray diffraction, scanning electron microscope, transmission electron microscope, dielectrics and ferroelectric measurements. The particle size of as-synthesized compounds and the intensity of diffraction peaks decline obviously as the milling time rises due to the compression stress, shear friction and other mechanical forces, which are created inside ball mill jars. Investigation of dielectric properties (frequency dependent) displayed the boosted tendency of dielectric constant with increased co-doping concentration. Elaborated analysis of impedance data at selected sets of frequency/temperature estimates the grains influence and boundaries in the capacitive and resistive parameters of the synthesized samples. An elaborated investigation of the impedance spectroscopy spectrum evidently exhibited the size dependence impedance/dielectric relaxation features of the synthesized compounds. The frequency and/temperature dependence of conductivity (alternating current) confirmed the universal power law of Jonscher. The observed ferroelectric hysteresis loop trend reveals that the nanoceramic holds good ferroelectric properties. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO 3 ), one of the most prominent members of multiferroics, has multiple promising characteristics useful for multifunctional applications. Multi-doped (Cd, Ti) complex bismuth ferrite [i.e., Bi(Cd 1/4 Ti 1/4 Fe 1/2 )O 3 ] ceramic was synthesized through a mixed-oxide route. X-ray structural analysis of the prepared material provides its basic crystal data of a single-phase orthorhombic system. The scattered crystallite size and lattice strain of the material were estimated using Scherrer and Williamson–Hall approaches respectively using X-ray diffraction peaks. Analysis of the micrograph of field emission scanning electron microscope shows uniform and densely packed grains on the surfaces of the pellet sample suggesting the formation of good quality and high-density sample. A significant effect of substitution of multiple elements at the Fe-site on dielectric constant and tangent loss of BiFeO 3 has been observed. Detailed studies of temperature (25–500 °C) and frequency (1–1000 kHz) dependence of impedance and ac-conductivity have provided the effect of grains and grain boundaries on the conduction mechanism and dielectric relaxation of the material. Based on the magnetic measurements, it is concluded that (Cd, Ti) modified bismuth ferrite has provided saturation magnetisation (M s ) and coercivity (H c ) of 2.66 emu g −1 and 653.75 Oe respectively which are consistent with those of many compounds of similar type. [ABSTRACT FROM AUTHOR]