Interfacial magnetic coupling between Fe nanoparticles in Fe–Ag granular alloys

The role of the interface in mediating interparticle magnetic interactions has been analysed in Fe50Ag50 and Fe55Ag45 granular thin films deposited by the pulsed laser deposition technique (PLD). These samples are composed of crystalline bcc Fe (2–4 nm) nanoparticles and fcc Ag (10–12 nm) nanoparticles, separated by an amorphous Fe50Ag50 interface, occupying around 20% of the sample volume, as determined by x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), and high resolution transmission electron microscopy (HRTEM). Interfacial magnetic coupling between Fe nanoparticles is studied by dc magnetization and x-ray magnetic circular dichroism (XMCD) measurements at the Fe K and Ag L2, 3 edges. This paper reveals that these thin films present two magnetic transitions, at low and high temperatures, which are strongly related to the magnetic state of the amorphous interface, which acts as a barrier for interparticle magnetic coupling

Interfacial magnetic coupling between Fe nanoparticles in Fe-Ag granular alloys

The role of the interface in mediating interparticle magnetic interactions has been analysed in Fe 50Ag 50 and Fe 55Ag 45 granular thin films deposited by the pulsed laser deposition technique (PLD). These samples are composed of crystalline bcc Fe (2-4nm) nanoparticles and fcc Ag (10-12nm) nanoparticles, separated by an amorphous Fe 50Ag 50 interface, occupying around 20% of the sample volume, as determined by x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), and high resolution transmission electron microscopy (HRTEM). Interfacial magnetic coupling between Fe nanoparticles is studied by dc magnetization and x-ray magnetic circular dichroism (XMCD) measurements at the FeKand Ag L 2, 3edges. This paper reveals that these thin films present two magnetic transitions, at low and high temperatures, which are strongly related to the magnetic state of the amorphous interface, which acts as a barrier for interparticle magnetic coupling.This work was partially supported by the Spanish CICYTMAT2008- 06542-C04 grant. Work at Argonne is supported by the US Department of Energy, Office of Science, under contract No DEAC-02-06CH11357. M A Laguna-Marco, J Alonso and R Boada acknowledge the Ministerio de Ciencia y Tecnología of Spain for Postdoctoral and PhD grants.Peer Reviewe