Tuning the Magnetic Phases of Iron Oxide Nanocubes

The magnetic properties and biocompatibility of iron oxide nanoparticles allow for many uses in biomedical settings and other applications. Studies also indicate that iron oxide nanostructures could be used to enhance magnetic memory storage devices. This project aims to tune the different phases of iron oxide in order to optimize the magnetic properties. In the experiment, 30 nm iron oxide nanocubes were synthesized using a thermal decomposition process. After synthesis, the nanocubes were annealed at temperatures ranging from 150-300°C and for times ranging from 2-8 hours in order to optimize the iron oxide volume fractions. The 300 K magnetometry measurements showed that the coercivity increased after annealing whereas the 10 K magnetometry measurements displayed the opposite trend. However, the 10 K measurements showed an overall increase in coercivity due to the decrease in thermal energy as predicted by Bloch’s relation. Overall, these results not only indicate the kind of the magnetic behavior of the nanocubes (i.e., ferrimagnetic, superparamagnetic, etc.) but also help describe the crystallinity of the nanocubes since the crystallinity tends to increase with coercivity. Extensions of this project include using an inert gas while annealing to control the oxidation.