Magnetization dynamics of iron oxide super paramagnetic nanoparticles above blocking temperature

Abstract

Magnetic characterizations of synthesized superparamagnetic Iron-Oxide nanoparticles have been carried out at various constant temperatures. As magnetization versus magnetic field (M−H) curve verifies the superparamagnetic nature of nanoparticles, M−H curve has been analysed to verify the superparamagnetic behavior of synthesized nanoparticles. Structure and morphology has been characterized by X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM).The XRD confirms the cubic spinel structure of prepared nanoparticles. Cubical shaped morphology is observed from the TEM image. The reaction temperature is observed to critically affect the particle size and modification of magnetic properties. Further, the M−H curve has been analysed to fit the Langevin function and size distribution of nanoparticles has also been studied. The experimentally measured magnetization curve found to fit the theoretically calculated Langevin function satisfactorily. The typical intrinsic magnetization of prepared nanoparticles show superparamagnetism and observed to follow the sigmoid function with negligible remanence and coercivity value. The particles are found to be agglomerated with a size distribution of 10 - 30 nm.