Large coercive field in magnetic-field oriented ε-Fe2O3 nanorods

We report the fabrication and magnetic coercive field of oriented epsilon-Fe(2)O(3) nanorods. Oriented epsilon-Fe(2)O(3) nanorods embedded in SiO(2) matrix were obtained by a sol-gel method under an applied external magnetic field. The longitudinal axis, which corresponds to a-axis of the crystal structure of epsilon-Fe(2)O(3) nanorods, was oriented parallel to the direction of external magnetic field. The sample achieved a magnetic coercive field along the longitudinal axis of 23.4 kOe, which is the largest value among metal oxide-based magnetic materials. The shape of the magnetic hysteresis loop is well understood by considering the magnetization rotation process and the uniaxial magnetic anisotropy. (c) 2008 Elsevier B.V. All rights reserved.