Superparamagnetic behavior of indium substituted NiCuZn nano ferrites

Nano structured indium substituted NiCuZn ferrites with chemical composition Ni0.5Cu0.25Zn0.25Fe2−xInxO4 (0.0≤x≤0.4) were prepared using citrate-gel method. The XRD analysis confirmed the formation of single phased cubic spinel structure with a crystallite size ranging from 25 to 34 nm. The morphology of the prepared samples was studied using transmission electron microscopy and the thermal growth of the samples was analyzed by thermo gravimetric analysis and differential thermal analysis. Magnetic properties such as the Curie temperature and the temperature dependence magnetization studies of the samples were carried out using vibrating sample magnetometer. From the temperature dependence of both the field cooled and Zero field cooled magnetization measurements in the temperature range 50-350 K under an applied field of 500 Oe, the blocking temperature (Tb) was estimated to be 325 K. Above Tb the material shows superparamagnetic behavior which makes the material desirable for biomedical applications.