Superparamagnetic cobalt ferrite nanoparticles: Effect of temperature and base concentration

Abstract

Cobalt ferrite nanoparticles were coprecipitated in air medium using NH3, and the effects of temperature and base concentration on the properties were studied. X-ray diffraction (XRD) technique and Fourier transform infrared spectroscopy were used to investigate the structural properties of the samples. Particle sizes and shapes were determined by a transmission electron microscope (TEM). Magnetic measurements were done using vibrating sample magnetometer at room temperature. The proper reaction temperature was found to be 80 A degrees C for the synthesis of superparamagnetic cobalt ferrite nanoparticles. The effect of base concentration on the properties of the superparamagnetic nanoparticles was investigated under this temperature. The magnetization values of cobalt ferrite nanoparticles increased as the base concentration increased and reached to a value of 32.4 emu/g with zero coercivity. The particle sizes (d (XRD), d (TEM), and d (VSM)) of cobalt ferrite nanoparticles were calculated from XRD patterns, TEM images, and magnetic data, respectively. It was observed that the d (TEM) and d (VSM) are similar to each other, and the d (XRD) are bigger than those with the similar trend of increase with the increase of base concentration.