Temperature mediated morphological and magnetic phase transitions of iron/iron oxide Core/Shell nanostructures

Understanding how thermal decomposition of Iron penta carbonyl transformed from spherical shaped Iron/Iron oxide Coe/Shell nanoparticles into flower shaped hollow nanoparticles followed by spherical shaped hollow nanoparticles is crucial scientifically as well as technologically. Presently, it is mentioned that how shape and size distribution of nanoparticles can be tuned by post annealed treatment in air environment. Crystal structure and phase of as synthesized and post annealed samples were confirmed by X-ray diffraction (XRD) and Raman spectroscopy. Morphological transformations were estimated with transmission electron microscope (TEM). Particle size and distribution was attained by using free software ImageJ and it has been observed that as synthesized and heat treated samples at 1000 °C have particle size of ∼9 nm and ∼18 nm, respectively by XRD calculations which is in good agreement with TEM. The measurements taken by vibrating sample magnetometer (VSM) show interesting change in magnetic phase from superparamagnetic phase of as synthesized nanoparticles to strong ferromagnetic phase after heat treatment. Low temperature magnetic characterizations of Core/Shell nanoparticles are explained in detail in some extent by physical property measurement system (PPMS).