Cationic Disorder and Surface Effects on the Magnetic Properties of Co₃O₄ Nanoparticles Synthesized by Co‐Precipitation with Addition of Sucrose

In this study, we have examined the role of adding sucrose chelating agent on the structural and magnetic properties of single phase Co₃O₄ nanoparticles. The samples are obtained using a co‐precipitation chemical method with varying concentrations of sucrose. The X‐ray diffraction data, analyzed through Rietveld refinement, and the Scanning Electron Microscopy and Transmission Electron Microscopy images indicate that the average particle size, their shape, and size distribution depend on the sucrose concentration. The smallest size obtained was around 6 nm for the sample grown with 0.32 mol/L of sucrose. Magnetic measurements as a function of magnetic field and temperature indicate that the samples exhibit superparamagnetic behavior below 10 K, and the peak in susceptibility decreases with increasing sucrose concentration, reaching a minimum value of 4.5 K for the sample grown with 0.32 mol/L of sucrose. After subtracting the high‐field linear contribution, likely attributed to superparamagnetism, we observe saturation in the Mvs.H curves measured at T = 2 K. The saturation value is approximately 1.2 emu/g for all samples. Since bulk Co₃O₄ is expected to be antiferromagnetic at T = 40 K, this value of magnetization may be linked to the degree of cationic disorder in the occupation of Co²⁺ and Co³⁺ ions between A and B sites.

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