Magnetic properties of Co_1−xNi_x/2Sr_x/2Fe₂O₄ (x = 0−1) ferrite nanoparticles synthesized by self-assembling media of reverse micelles

Co_1−xNi_x/2Sr_x/2Fe₂O ferrite nanoparticles were prepared using reverse micelle process. Mean particle size of pure ferrite nanoparticles is approximately 9 nm as determined by transmission electron microscopy (TEM). The heating thermograms of samples confirmed that there are no hydroxides in the ferrites fabricated via reverse micelles. Vibrating sample magnetometer (VSM) was employed to probe magnetic properties of nanosized. It was found that with increasing the amount of Ni and Sr in nanosized ferrites, the saturation magnetization decreases. Magnetic dynamics of the samples was studied by the measurement of AC magnetic susceptibility versus temperature at different frequencies. The phenomenological Néel – Brown and Vogel – Fulcher models were employed to distinguish between interacting or non-interacting system. Results show that there is strong interaction between fine particles.