Electrical, dielectric and magnetic properties of Sn-doped hematite (?-SnxFe2-xO3) nanoplates synthesized by microwave-assisted method

Abstract

Hematite nanoparticles are of interest due to their exceptional electrical and magnetic behavior and various technological applications. The doping of hematite can vary its electrical and magnetic properties. Here, we report the effect of different concentrations of Tin doping on electrical, dielectric and magnetic properties of hematite synthesized by the microwave-assisted method. Tin-doped ?- Fe<inf>2</inf>O<inf>3</inf> (?-Sn<inf>x</inf>Fe<inf>2-x</inf>O<inf>3</inf>) samples have been characterized using XRD, TGA, FESEM, and EDS (mapping). XRD pattern shows the rhombohedral structure of ?-Sn<inf>x</inf>Fe<inf>2-x</inf>O<inf>3</inf>. The synthesized samples have nanoplate like structure with a uniform distribution of tin throughout the sample. Electrical properties were investigated using dielectric and impedance studies. The dc resistivity and ac conductivity decreased with increase in concentration up to x = 0.06 (Sn<inf>0.06</inf>Fe<inf>1.94</inf>O<inf>3</inf>). However, it increased with further increase in the concentration of tin. The hopping of electrons between Fe3+ and Fe2+ in octahedral sites accounts for the observed conduction behavior. A single semi-circle of the cole-cole plot for ?-Sn<inf>x</inf>Fe<inf>2-x</inf>O<inf>3</inf> indicates the dominant grain boundary effect in conduction. Dielectric constant and loss factor reveal the dielectric relaxation in ?-Sn<inf>x</inf>Fe<inf>2-x</inf>O<inf>3</inf> samples. The magnetic properties were studied using VSM, which shows that ?-Sn<inf>x</inf>Fe<inf>2-x</inf>O<inf>3</inf> are antiferromagnetic/weakly ferromagnetic in nature with high coercivity. © 2017 Elsevier B.V.