We report magnetic properties of macroporous magnetic materials with highly ordered spherical voids prepared by an electrochemical technique. The interstitial sites in close-packed arrays of colloidal silicas were filled by the electrodeposition of Fe, Co, and Fe3O4. The silica templates were removed by soaking the deposited templates into a 2% HF solution. SEM images of the template-free macroporous magnetic materials clearly exhibit spherical voids arranged in a three dimensionally ordered structure. The magnetization curves of the Fe and Co films show a decreasing tendency with decreasing temperature, which might be associated with magnetic polarization and domain wall propagation. On the other hand, the Fe3O4 film exhibits a typical ferromagnetic behavior but has the reduced Curie temperature, which is due to the 2D Heisenberg type of the Fe spins. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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