Structural, AC conductivity, conduction mechanism and dielectric properties of La_0.62Eu_0.05Ba_0.33Mn_0.85Fe_0.15O₃ ceramic compound

The new perovskite compound La_0.62Eu_0.05Ba_0.33Mn_0.85Fe_0.15O₃ was successfully synthesized via the sol–gel process. X-ray diffraction revealed that our sample is pure and crystallizes in the orthorhombic structure with Pbnm space group. Electrical properties were performed using the complex impedance spectroscopy technique in the range of frequency (40–10 MHz) and at various temperatures (80–400 K). AC-conductivity results are well described by the universal Jonsher’s power law at low temperatures and the DC-conductivity data are well fitted by the small polaron hopping model at high temperatures. Impedance results show a negative temperature coefficient of resistance (NTCR) which discloses the semiconductor behaviour of the studied sample. Nyquist plots were well fitted by an equivalent circuit involving the contribution of grain and grain boundaries in the conduction process. Giant dielectric values, useful in electronic devices, were obtained. Moreover, a relaxation diffuse phase transition is attributed to a strong heterogeneity in A and B sites of the studied perovskite.