Effect of pH value on multiferroic properties of barium ferrite ceramics prepared by sol–gel method.

• The effect of pH value of precursor solution on the microstructure and magnetoelectric properties of BaFe 12 O 19 nanoparticles and ceramics were studied. • The change of pH value of precursor solution causes large distortion of hexagonal flake grains of ceramics, which reflects the deformation of hexagonal cells in BaFe 12 O 19 crystal and leads to the asymmetry of local lattice. • The ferroelectric hysteresis loop and hysteresis loop indicate the multiferroic properties of the prepared ceramics at room temperature. The effect of ceramics leakage current on ferroelectric property were further studied. In this paper, BaFe 12 O 19 (BaM) ceramics at different pH values were prepared by sol–gel method. Effects of pH value on the microstructure, electrical as well as magnetic properties were systematically studied. XRD indicate that the ceramics were mainly BaM. However, with the pH value increasing further, the BaFe 2 O 4 impurity phase appears gradually in both powders and ceramics due to the degree of complexation between citric acid and metal cations and other reasons. SEM results show that the grain size of ceramics decreases from 2.28 μm to 1.35 μm with the pH value increase from 4 to 8. It is found that room temperature dielectric constant, residual polarization, and saturation magnetization of the ceramics is the largest when the pH value of the solution is 4, which are 0.108 μC/cm2 and 32.829 emu/g, respectively. The dielectric constant and residual polarization of ceramics decrease with the increase of pH value. The ferroelectric and magnetic hysteresis loops have confirmed room-temperature multiferroic properties of the prepared ceramics. It laid the foundation for the further development of new room temperature single-phase multi-iron materials. [ABSTRACT FROM AUTHOR]