Tailoring the dielectric behavior of BaTiO3 via incorporation of vanadium-substituted barium hexaferrite and thermal effects

Abstract

Composite ceramics of a BaTiO₃ (BTO) matrix incorporated with varying quantities of BaFe_11.96V_0.04O₁₉ (BVFO) hexaferrite were investigated. The successful creation of the intended composites was verified using XRD, FE-SEM, and EDX spectroscopy, which revealed the coexistence of the two-component phases. There were no further phases other than the initial components, indicating that the adopted approach is efficient in obtaining the desired composites. The BTO phase is represented by spherical grains, while the BVFO hexaferrite phase is represented by plate-like grains. The dielectric properties were tested in a frequency range of 1 Hz–3 MHz and at different temperatures of 30–120°C using an impedance spectroscopy instrument. At low frequencies, temperature-dependent dipolar and interfacial polarizations have a remarkable effect. Conversely, ionic and electronic polarizations are less temperature-dependent, which became more effective at high frequencies. The observed effects in dielectric measurements are a result of combined electron and polaron jumping conduction mechanisms. The Cole-Cole plots showed the dominant effect of grains and grain boundaries for all compositions but also revealed the negligible influence of the electrode. Additionally, it was crucial to avoid extremely large losses, which is shown by the determined dielectric tangent loss.