Cationic Disorder and Surface Effects on the Magnetic Properties of Co3O4$\left(\text{Co}\right)_{3} \left(\text{O}\right)_{4}$ Nanoparticles Synthesized by Co‐Precipitation with Addition of Sucrose

Abstract

Herein, the effect of adding sucrose chelating agent on the structural and magnetic properties of single‐phase Co3O4 nanoparticles is examined. The samples are obtained using coprecipitation with varying concentrations of sucrose. The X‐ray diffraction data 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 is around 6 nm for the sample grown with 0.32 mol L−1 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−1 of sucrose. After subtracting the high‐field linear contribution, likely attributed to superparamagnetism, saturation in the M vs. H curves measured at T = 2 K is observed. The saturation is approximately 1.2 emu g−1 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 and ions between A and B sites.