Cation distribution of Ni-Zn-Mn ferrite nanoparticles

Highlights: • Mn substituted Ni-Zn ferrite nanoparticles were prepared by sol-gel autocombustion method. • Cation distributions were determined using Rietveld structural refinement method. • Derived cation distributions were confirmed by X-ray and magnetic data. • Structural and magnetic data were correlated to changes in composition and cation distribution. Mn substituted Ni-Zn ferrite nanoparticles, Ni_0.4Zn_0.6-xMn_xFe₂O₄ (x = 0.00–0.25 in steps of 0.05), using metal nitrates were prepared by sol-gel autocombustion in citric acid matrix. The samples were examined by X-ray diffraction and vibrating sample magnetometer techniques. Rietveld structural refinements using the XRD data were performed on the samples to consolidate various structural parameters like phase (spinel), crystallite size (24.86–37.43 nm), lattice constant (8.3764–8.4089 Å) etc and also to determine cation distributions based on profile matching and integrated intensity ratios. Saturation magnetization values (37.18–68.40 emu/g) were extracted from the measured M−H loops of these nanoparticles to estimate their magnetic moments. Experimental and calculated magnetic moments and lattice constants were used to confirm the derived cation distributions from Rietveld analysis. The results of these ferrite nanoparticles are discussed in terms of the compositional modifications, particle sizes and the corresponding cation distributions as a result of Mn substitutions.