Interface alloying effects in the magnetic properties of Fe nanoislands capped with different materials

We show that Fe nanoislands capped with Al, Pd, and Pt protecting layers include an alloy at the interface with the capping layer, which explains the previously known capping layer dependence on the interparticle magnetic coupling. Vibrating sample magnetometry results, for instance, are evidencing...

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Bibliographic Details
Authors: Huttel, Yves, Navarro, E., Telling, N. D., Van der Laan, G., Pigazo, F., Palomares, F. Javier, Quintana Rodríguez, Carmen, Román, Eduardo H., Armelles Reig, Gaspar, Cebollada, Alfonso
Format: article
Publication Date:2008
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/11795
Online Access:http://hdl.handle.net/10261/11795
Access Level:Open access
Keyword:Alloying
Aluminium
Ferromagnetic materials
Iron
Island structure
Magnetic circular dichroism
Magnetic moments
Magnetic particles
Magnetisation
Nanostructured materials
Palladium
Platinum
X-ray photoelectron spectra
Description
Summary:We show that Fe nanoislands capped with Al, Pd, and Pt protecting layers include an alloy at the interface with the capping layer, which explains the previously known capping layer dependence on the interparticle magnetic coupling. Vibrating sample magnetometry results, for instance, are evidencing a reduction in the magnetization measured under a magnetic field of 15 mT, which is larger in the case of the Al capping and which is due to the presence of a magnetically dead interface alloy. This reduction is also observed at the atomic level using x-ray magnetic circular dichroism measurements, showing a capping layer dependence of the Fe magnetic-moment reduction that is similar for the Pd and Pt capping, and stronger for the Al capping. The trend in the magnetic properties as a function of the capping layer is explained in the light of x-ray photoemission spectroscopy results that evidence the formation of alloys at the interface between the Fe nanoislands and the capping layers. The present results highlight the strong influence of interface alloying in systems of reduced dimensionality. In particular, it is shown that the magnetic properties are strongly affected at both the atomic and macroscopic level.