Facile route for synthesis of Er doped Cobalt Nanoferrites and Investigation on Structural, Magnetic and Humidity sensor properties

In this work, Er 3+ doped Cobalt Nanoferrite particles CoEr x Fe 2−x O 4 (x = 0.0, 0.01, 0.03, 0.05) were synthesized using optimized citrate-gel auto-combustion method and analyzed for Humidity sensor applications. Preliminary X-ray diffraction and Raman spectroscopic studies and confirm the formation of single-phase spinel structure. Average crystallite sizes from Williamson-Hall method are in the range 28 nm to 32 nm, which are in close agreement with TEM data. Temperature dependent magnetization ZFC-FC curves shows above room temperature blocking temperature. Hysteresis loops obtained by vibrating sample magnetometry clearly enhances the magnetization of cobalt ferrite. Electrical resistance measurements in different relative humidity conditions (RH 10–95%) and frequencies were done using a High Frequency LCR Meter. Er doped Cobalt ferrite samples shows a decrease in electrical resistance and improved sensitivity compared to the pure ones. The variation of Resistance with respect to humidity conditions suggested that Er doped Cobalt ferrite nanoparticles are potentially suitable for resistive humidity sensor applications.