Superparamagnetism and the Morin transition in amorphous and crystalline iron oxide systems

This work studies the magnetic properties of microcrystalline iron oxides. These were produced from iron-nitrate under a variety of conditions using a simple hydrolysis and baking technique. In particular the authors wished to observe superparamagnetic behaviour of the particles produced. The authors discuss the relaxation phenomena and Morin transitions observed in the hematite and ferrihydrite obtained and investigate how this is affected by noncrystallinity and particle volume. (Auth.)