Syntheses of iron oxide nanoplates by hydrothermal treatment of iron-oleate precursor and their magnetization reversal

Magnetic iron oxide (Fe3-xO4) nanoplates with a high aspect ratio (lateral size/thickness ratio of >50) were synthesized via a facile hydrothermal treatment of an iron-oleate precursor. The magnetic domain configuration of the Fe3-xO4 nanoplates was observed by magnetic force microscopy (MFM). Single domain magnetic polarity was observed in the remnant state of isolated Fe3-xO4 nanoplates, with a lateral size of ca. 300 nm and thickness of 7.6 nm. The magnetization orientation of isolated Fe3-xO4 nano plates was mainly determined by the magnetic shape anisotropy originating from their high aspect ratio. Magnetization reversal occurred via coherent rotation upon switching the external magnetic field, rather than by domain wall nucleation. Micro-magnetic simulations based on the Landau-Lifshitz Gilbert equation supported the conclusions drawn from the experimental results. (C) 2017 Elsevier B.V. All rights reserved.