Effect of rare earth Nd3+ doping contents on physical,structural,and magnetic properties of Co-Ni spinel ferrite nanoparticles

Rare earth(RE) low doping has a significant influence on the structural,morphological,and magnetic properties of spinel ferrite nanoparticles.Therefore,rare earth neodymium(Nd) oxide was fully doped into spinel ferrite with a composition of Co0.80Ni0.20NdxFe2-xO4(x=0.0,0.05,0.10,and 0.15) using the sol-gel auto combustion method.Structural analysis of the synthesized samples with low doping of Nd using X-ray diffraction(XRD) and Rietveld refinements reveals a pure single-phase cubic structure,while the second phase appears with increasing content of Nd3+at x=0.10 and 0.15.Scanning electron microscopy(SEM) and high-resolution transmission electron microscopy(HR-TEM) show well-shaped spherical grains within the nanometer range of the pure Co0.80Ni0.20Fe2O4sample,while larger grains with the presence of agglomeration are observed with doping of Nd3+into the spinel ferrite nanoparticles.The magnetic parameters,i.e.,saturation magnetization Ms,remanence and magnetic moments exhibit decreasing trend with Nd3+doping and Msvalues are in 65.69 to 53.34 emu/g range.The coercivity of the Nd-doped Co-Ni spinel ferrite sample was calculated to be 1037.76 to ～827.24 Oe.This work demonstrates remarkable improvements in the structural and magnetic characteristics of Nddoped Co-Ni spinel ferrite nanoparticles for multiple versatile applications.