Magnetic properties of nanosize NiFe2O4 particles synthesized by sol–gel auto combustion method

Abstract A nitrate–citrate gel was prepared from metal nitrates and citric acid by sol–gel auto combustion process, in order to synthesize NiFe 2 O 4 ferrite. X-ray diffraction showed the formation of NiFe 2 O 4 and the inclusion of α-Fe 2 O 3 . However, with increasing the calcination temperature, this inclusion phase (α-Fe 2 O 3 ) decreased. TEM was also used to characterize the microstructure of the nanosize NiFe 2 O 4 . Magnetization hysteresis of the nickel ferrite powders was performed at room temperature. It is shown that this powder which is composed of crystalline NiFe 2 O 4 monophase, exhibited M s = 54 (emu/g) at magnetic field of 2 (kOe).