Abstract
Typically the value of the magnetostrictive coefficient (lambda) observed for bulk magnetic materials such as cubic ferrites is 10(-6). However, giant magnetostriction (lambda <10(-3)) is only observed in a few bulk intermetallic materials based on alloys of rare earth and iron such as TbFe, TbFe2, DyFe2 and Terefenol-D. While giant magnetostriction is known in nanostructured films, we show for the first time, this phenomenon occurs in magnetic nanoparticles. By using in-field small angle X-ray scattering (SAXS) as a tool, we demonstrate that a 4% relative change in dimension of the particle can be observed in 5.0 nm Fe3O4 nanoparticles at room temperature with 1 kG magnetic field. Also, we propose that the observed values are clue to interaction effects and magnetoelastic coupling of particle magnetic moments and external magnetic field. (C) 2011 Elsevier B.V. All rights reserved.