Role of copper on structural, magnetic and dielectric properties of nickel ferrite nano particles.

Copper doped nickel ferrites Ni (1− x ) Cu x Fe 2 O 4 (where x =0.2, 0.4, 0.6) nanoparticles are prepared by co-precipitation method and sintered at 600 °C. The XRD study confirms the formation of single-phase cubic spinel Ni–Cu ferrites. The particle size increases with Cu substitution. FT-IR spectra confirm the absorption bands around 554–547 cm −1 for the tetrahedral sites and around 448–450 cm −1 for the octahedral sites. The inclusion of copper shifts the tetrahedral band to lower values. The saturation magnetization ( M s ) and remanent magnetization ( M r ) decrease with increase in copper concentration and the coercivity ( H c ) is found to increase for all the compositions sintered at 600 °C. The dielectric constant decreases drastically for all the compositions and reaches a constant value. These nanoparticles can be tested for humidity sensing applications. [ABSTRACT FROM AUTHOR]