Effect of gallium substitution on the structural, dielectric and magnetic properties of bismuth ferrite / Nur Zarifah Syazwani Noreaini

Gallium doped in Bi-site of Bi1-xGaxFeO3 (BGFO) ceramic with x = 0.00, 0.01, 0.02 and 0.03 was synthesized by using solid state reaction method. The prepared samples were calcined at 825°C for 2 hours. In this study, the effect of Gallium substitution at A-site on the structural and dielectric properties were investigated by using X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Electrical Impedance Spectroscopy (EIS). Furthermore, magnetic properties of Bismuth Ferrite (BFO) and BGFO were studied by using Vibrating Sample Magnetometer (VSM). The substitution of Ga3+ which possess smaller ionic radius compared to Bi3+ could help in reducing volatility, enhanced dielectric properties and increased the magnetization values. XRD analysis revealed single phase nature until 0.02 Gallium concentrations and there was no structural changes as Ga dopant had entered the BFO structure. On the Ga3+ substitutions for microstructural analyses indicate the grain reductions as well as more uniformly distribution grain were observed by using SEM. Meanwhile, the influence of Gallium substitution on dielectric measurements was examined by using EIS at room temperature with frequency ranging up to 1MHz and the dipole relaxation phenomenon can be seen in all samples un-doped BFO and Gallium doped samples. Furthermore, Gallium doped to the BFO system showed significant enhancement in dielectric constant and dissipation factor. The magnetic studies were analyzed by using VSM where M-H hysteresis loop on Ga3+ ion substitution shows the enhancement in saturation magnetization at room temperature up to magnetic field 6 kOe compared to un-doped Bismuth Ferrite which antiferromagnetic behavior was observed.