Characterization of Pb(Fe1/2Nb1/2)O-3 ceramic as a potential candidate for photovoltaic and magnetoelectric applications

An impurity-free Pb(Fe1/2Nb1/2)O3 (PFN) ceramic was prepared using a conventional solid-state reaction method with precisely controlled sintering temperature. The PFN ceramic exhibits monoclinic symmetry and shows a dense morphology with equiaxed grains of about 1-2 mu m. It exhibits a diffused phase transition at approximately 381 K. From the data of dielectric loss tangent and the imaginary parts of impedance and electrical modulus, a non-Debye type dielectric relaxation was investigated, and it was found that the short-range hopping of oxygen vacancies contributes to the dielectric relaxation and the relaxation time distribution is temperature independent. The PFN ceramic exhibits slim ferroelectric hysteresis loops and a linear magnetic hysteresis loop, indicating that the PFN ceramic is paramagnetic; the band gap is estimated to be 2.04 eV. Photoconductivity and photovoltaic responses with a nonzero open-circuit voltage and short-circuit photocurrent were detected. Moreover, magnetoconductivity was measured. This work implies that the PFN ceramic is a potential candidate for magnetoelectric and photovoltaic applications.