Transport properties of Ba-doped BiFeO3 multiferroic nanoparticles

Multiferroic nanoparticles of Bi1−xBaxFeO3 (BiBaFeO3); (x = 0.10, 0.15, 0.20 and 0.25 mol%) samples were prepared using conventional solid-state method. The nanostructural and transport properties of the prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrical conductivity. XRD patterns show the formation of BiBaFeO3 with single-phase rhombohedral-hexagonal structure. The particles sizes were found to be in the range 20–33 nm. SEM micrograph revealed the nanostructure consisting of small, randomly oriented and non-uniform grains. Dc conductivity shows that all samples are semiconductor and the maximum was found at x = 0.15 mol%. This increase of the conductivity can be attributed to the decrease in grain boundary scattering due to the reduction in crystallite size. The calculated activation energy for the multiferroic nanoparticles was found to be 0.413–0.929 eV. The conduction was confirmed to obey non-adiabatic small polaron hopping (SPH). The electron–phonon interaction coefficient (γp) was calculated and found to be in the range of (12.79–27.21). The hopping carrier mobility varied from 1.85 × 10−7 cm2V−1s−1 to 8.01 × 10−13 cm2V−1s−1 at 418 K. The conductivity was primarily determined by hopping carrier mobility.