The effects of N2 atmosphere annealing on the physical properties of BiFe0.5Mn0.5O3 ceramic

Abstract

Multiferroic BiFe0.5Mn0.5O3 (BFMO) was elaborated by the conventional solid-state method under ordinary sintering conditions (air) and N2 atmosphere at 1193 K, and the effects of the two different atmospheres on the structural properties were studied. Indeed, it was found that BFMO prepared in the atmospheric air exhibited an impurity phase, BFMO annealed under an N2 atmosphere, displayed an intensity of secondary phase that decreased significantly (As for the Rietveld analysis), indicating that BFMO annealed under N2 flow crystallized in rhombohedral structure with R3c space group. The phase crystallinity was confirmed by Raman spectroscopy. Moreover, a dielectric study revealed the enhancement of dielectric permittivity ε’r and a low dielectric loss. Concerning the electrical hysteresis loop at room temperature, it indicated that BFMO sample exhibited ferroelectric characteristics. Besides, the impedance spectroscopy and conductivity were investigated in the frequency range of 102-106 Hz. Nyquist plots indicated the presence of only grain contributions. Furthermore, the conduction mechanism was evaluated by Ac conductivity using Jonsher low. From the thermal variation of the exponent S, it was concluded that the model of Correlated Barrier Hopping (CBH) and the Non-overlapping Small Polaron Tunneling (NSPT) were the dominant conduction mechanisms present in our sample. From the magnetic measurement, FC and ZFC were reported to show the weak ferromagnetism character of our sample. The obtained physical properties of BFNO at room temperature suggest that this material can be used in technological applications.