Morphology and Magnetic Properties of Platelet γ-Fe<sub>2</sub>O<sub>3</sub> Particles

Abstract

The morphology and magnetic properties of platelet i-FeOOH and £-Fe2O3 particles were studied to use hysteresis-loss heating of ferromagnetic particles in magnetic hyperthermia or thermoablation. The platelet i-FeOOH particles were prepared through the formation of a precipitant followed by the hydrothermal treatment of the precipitant. The shape of the i-FeOOH particles changed from elongated to plateletlike depending on the quantity of ethanolamine in the precipitant. The size of the platelet i-FeOOH particles was reduced from 90­120 to 40­ 60 nm as the precipitant temperature was lowered in the range from 5 to 13°C. The formation of dimples was observed during the dehydrating process from i-FeOOH to i-Fe2O3, and was confirmed from the increase in the BET surface area of the i-Fe2O3 particles. The particle size and the coercive forces of the platelet £-Fe2O3 particles were in the range 30­100 nm and 7.6 kA/m (96Oe) to13.5 kA/m (169Oe), respectively. [doi:10.2320/matertrans.M2012195]