Tuning Nickel Spinel Ferrite Using Mn-Li Ion as Dopant for Potential Applications in Various Devices

NiFe2-2x(Mnx-Lix)O4 (x = 0.1, 0.2, 0.3, 0.4, 0.5) spinel ferrite nanoparticles have been synthesized using coprecipitation method. Structural characterization of nano powder was carried out using X-ray diffraction technique. XRD results confirmed the formation of single phase cubic inverse spinel ferrite, with average-crystallite sizes of 11–15 nm. Dielectric measurements showed the normal MaxWell Wagner type dielectric dispersion due to interfacial polarization. Ac conductivity of NiFe2-2x(Mnx-Lix)O4) varies from 10−5 to 10−4 (Ω cm)−1. Ac conductivity increases with increasing frequency. Decrease in impedance value is observed with increase in frequency. NiFe2-2x(Mnx-Lix)O4 shows superparamagnetism with optimum values of remnant magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were found as 11.0 emu/g, 0.90 emu/g and 71 Oe respectively for Mn-Li content of x = 0.3.