Spin-wave excitations in nanocrystalline Fe particles

Wires of composition Cu-15 vol%Fe, consisting of a Cu matrix and a body-centered cubic (BCC) Fe phase of fiber morphology have been prepared from rapidly solidified powders by extrusion and heavy cold drawing. Upon cold working, the thickness of the Fe ribbons decreases to 3.5 nm while the ribbon width drops to 27 nm. Thermal dependence of magnetization exhibits a decrease with temperature markedly faster than in bulk BCC-Fe. This dependence is found to arise from the confinement of low-energy spin waves due to the elongated shape of Fe nanoribbons. © 2003 Elsevier B.V. All rights reserved.