Magnetic Iron Oxides

Over breathed, ever stirring,
life from tired metal pry,
roles juggled, never dropping,
faster than the watching eye.

The magnetic properties of iron oxides have had wide-ranging technological applications for many years, ranging from navigation with magnetite (or Lodestone) to modern high-density magnetic recording media and readhead devices. The two systems studied in this chapter concentrate on magnetite and maghemite (Fe$_3$O$_4$ and $\gamma$-Fe$_2$O$_3$). Mössbauer spectroscopy is particularly adept at investigating these materials and obtaining information on oxidation states and sample compositions and has been used extensively for both technological and fundamental research.[48]

The first section is a commercial study of the magnetite content in printer toner materials. The emphasis is on determining the ratio of magnetite to maghemite in the materials. The following section concerns the growth of thin films of magnetite upon various substrates, using Mössbauer spectroscopy to determine the growth quality and to confirm the growth of magnetite.