Free Growth of Iron Oxide Nanostructures by Sol-Gel Spin Coating Technique—Structural and Magnetic Properties

The study of on iron oxide, especially magnetite Fe₃O₄, in the form of thin films and nanostructures, is interesting due to its wide applications in data storage, biomedical, and spintronic devices. Seven different sols are synthesized with varying concentration from 1.8 to 0.6 mM using the sol-gel technique. The concentration of 1.4 mM results in a pure phase whereas others show mixed magnetite and maghemite phases. In addition, changes in film preferred orientation from (400) to (220) planes are responsible for changing the ferromagnetic behavior of films to ferrimagnetic with increased saturation magnetization. Free growth of iron oxide nanostructures, including nanoneedles and nanobrushes, are observed in scanning electron microscope images.