Structural, optical, magnetic and photoelectrochemical properties of (BiFeO3)1−x(Fe3O4)x nanocomposites

• Published in: Journal of sol-gel science and technology 2019-09, Vol.91 (3), p.624-633
• Main Authors: Baqiah, H., Talib, Z. A., Shaari, A. H., Dihom, M. M., Kechik, M. M. Awang, Chen, S. K., Liew, J. Y. C., Zainal, Zulkarnain, Mohd Fudzi, Laimy
• Format: Article
• Language: English
• Subjects: Bias; Bismuth ferrite; Ceramics; Chemistry and Materials Science; colloids; Composites; Crystallites; Density; Electron microscopes; Electron paramagnetic resonance; Electron spin; Energy gap; etc.; Exchanging; fibres; Glass; Hysteresis loops; Inorganic Chemistry; Iron oxides; Magnetic properties; Materials Science; Microscopes; Microstrain; Nanocomposites; Nanoparticles; Nanotechnology; Natural Materials; Optical and Electronic Materials; Optical properties; Original Paper: Nano-structured materials (particles; Photoelectric effect; Photoelectric emission; Photoluminescence; Physical properties; Spectroscopy; Spectrum analysis; Spin resonance; Transmission electron microscopy
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-019-05053-9

(BiFeO 3 ) 1 −x (Fe 3 O 4 ) x nanocomposites were prepared by dispersion of Fe 3 O 4 nanoparticles (NP) into sol–gel synthesised BiFeO 3 (BFO) matrix followed by calcination at 500 °C. Samples with x  = 0.0, 0.2, 0.33 and 0.5 were investigated using X-ray diffractions (XRD), UV–vis spectroscopy, photoluminescence spectroscopy (PL), transmissions electron microscopes (TEM), electron spin resonance (ESR), vibrating sample magnetometer (VSM) and photoelectrochemical (PEC) measurements. Formation of nanocomposites was confirmed by XRD and TEM. The XRD patterns showed presence of both BFO and Fe 3 O 4 phases without any secondary phases. The crystallite size of BFO (39.1–51.1 nm) is much bigger than that of Fe 3 O 4 (10.1–12 nm). Microstrain of BFO decreased for sample x  = 0.2 and 0.33 and then increased for x  = 0.5. Optical band gap of samples decreased from 2.5 eV for x  = 0.0–1.96 eV for sample x  = 0.5. The PL emission which centred at 428.1 eV for x  = 0.0 increased gradually for samples x  = 0.2 and 0.33 and then decreased for x  = 0.5. Exchange bias ( H EB ) was observed for hysteresis loops of all samples, and the highest value of H EB was 38.4 Oe for x  = 0.5. The g -values of the nanocomposites, ranged between 2.23 and 2.20, were higher than that of the BFO and Fe 3 O 4 components. The PEC measurement showed the photocurrent density increased with x . Finally, modulations of the physical properties of BFO/Fe 3 O 4 system were analysed and discussed in detail. (a) Low magnification TEM image of (BiFeO 3 ) x (Fe 3 O 4 ) x composites showing dispersion of Fe 3 O 4 small particles (some was indicated by white arrow) into BiFeO 3 matrix. (b) PL spectra of sample x  = 0.5, (c) Top view of PEC setup (where 1 : PC, 2 : Autolab system and 3: halogen lamp) (d) side view of PEC setup (4: PEC cell and 5 : manual chopper) and (e) Photocurrent against voltage under chopped illumination of x  = 0.5. Highlights (BiFeO 3 ) 1− x (Fe 3 O 4 ) x composites were successfully synthesised. Lattice parameter c of BFO decreased with increasing Fe 3 O 4 content, x . (BiFeO 3 ) 1− x (Fe 3 O 4 ) x composites shows fascinating physical properties, such as exchange bias. The (BiFeO 3 ) 1− x (Fe 3 O 4 ) x composites exhibited reduced optical band gap. PEC measurement showed the photocurrent density increased with x . The study showed a presence of interaction between the BiFeO 3 and Fe 3 O 4 resulting in modulated physical properties.