Relaxor multiferroic properties of nanostructured 0.30BaTiO3–0.52Bi2O3–0.18Fe2O3 mol% (BFBT) were prepared via the mechanical activation method. The mixed powders were ball milled at 10, 20, 30, 50 and 75 h to obtain nanostructured materials. Room temperature XRD patterns for these nanostructured materials at different ball-milling times were investigated. The ball milled of nanostructured BFBT at different ball-milling times is characterized and identified by FTIR. After 50 h, HRTEM revealed the nanostructure of BFBT with an average particle size of 27.86 nm. Dielectric characterization showed a broad and frequency-dependent diffusion in phase transition around 560 K that shifted to the higher temperature with increasing frequency. The dielectric diffusivity (Υ = 1.78) was calculated from the modified Curie–Weiss law. Dielectric permitivitty (ε′) data were fitted using the Vogel–Fulcher relation, confirming the relaxor nature. Furthermore, the slim P-E hysteresis loop demonstrates recoverable energy density (Wrec = 16.17 mJ/cm3) and energy storage efficiency (η = 89.3%) at 360 K. The Néel Temperature (TN = 394 K) was determined by the magnetic susceptibility measurements. The M-H date shows a weak ferromagnetic behavior of the 50 h mechanical milled sample. Therefore, the presented work provides guidelines for synthesizing nanostructured BFBT by mechanical milling for the development of high-potential lead-free energy storage applications.

No abstract

Nanostructured 0.52 Bi2O3–0.18 Fe2O3–0.30 PbTiO3 (BFPT) mol% sample was prepared via a high-energy planetary ball mill. To obtain nanostructured materials, the mixture was mechanically milled for 1, 2, 5, and 25 h. The heat treating process was applied to the milled BFPT sample at 673, 873, and 1073 K for 5 h. The amorphous natures of the as-milled and crystallized formed phases of the heat treated samples are examined using the X-ray diffraction (XRD) technique. HRTEM and XRD were used to confirm the amorphous nature and nanocrystallization of the milled and the heat treated BFPT samples, respectively. The effect of the heat-treatment temperature of BFPT samples on their dc electrical conductivity (σ), density (ρ), and oxygen molar volume (Vm) was studied. The results of the thermoelectric power indicate a p-type semiconducting behavior of the BFPT samples. The high temperature (above θD/2) dependent on conductivity was explicated by the small polaron hopping (SPH) model. While Greaves’ variable range hopping (VRH) model was studied at intermediate temperatures. The physical parameters determined from the best fits of these models were thought to be reasonable and consistent with the BFPT samples. The hopping carrier mobility was found to be the dominant factor for determining the conductivity in the BFPT samples. The electronic transport between Fe ions was primarily responsible for the conduction, which was shown to obey the adiabatic SPH.