Evidence of superparamagnetic nanoparticles from Mössbauer spectroscopy study of Co0.5Ni0.5-xSrxFe2O4 nanoparticles

Co0.5Ni0.5-xSrxFe2O4 powders with x values of 0.1, 0.2, 0.3, 0.4 and 0.5 were quickly produced using the Solution Combustion Synthesis (S.C.S.) method. The effects of strontium (Sr) concentrations on the structure, microstructure, and magnetic properties were investigated using a variety of characterization methods. The SC technique produced single-phase spinel ferrites with a space group of Fd-3m (JCPDS data: 01-074-5694) directly and did not require any additional heat treatment throughout the manufacturing process. The lattice parameter increased due to the addition of the Sr ions, but the redistribution of the various cations resulted in a drop in the fraction of the Fe3+ cations found in the (A) sites. The average crystallite size reduced from 23 to 19 nm. Scanning Electron Microscopy (S.E.M.) displays well-shaped spherical grains in the nanoscale region, but larger grains with agglomeration were discovered with Sr doping of spinel ferrite nanoparticles. Room temperature M & ouml;ssbauer spectra have a structure typical for superparamagnetic nanoparticles. To determine the distributions of iron ions at the A- and B- sites, the low-temperature measurements of M & ouml;ssbauer spectra were performed at 15K, where the effect of relaxation on the structure of M & ouml;ssbauer spectra is negotiable, the concentration of iron ions in A- and B-site were determined. It has been established that the substitution of Nickel ions for Strontium ions leads to the growth of Fe-A(3+)/Fe-B(3+) ratio from 0.75 to 0.89. In this study, we show the effect of Sr doping on the structure, morphology and magnetic properties Co-Ni ferrite nanoparticles, which are suitable for a wide variety of applications because of their adaptability.

Automated summary

In this study, Sr-doped Co-Ni ferrite nanoparticles were quickly synthesized using the Solution Combustion Synthesis method, and the effects of Sr concentration on the structure, microstructure, and magnetic properties were investigated. The results showed that Sr doping caused an increase in lattice parameter, redistribution of various cations, and a decrease in average crystallite size. Additionally, Sr doping led to grain agglomeration. The distribution of iron ions at the A- and B- sites were determined through low-temperature Mössbauer spectroscopy.