Growth and magnetic characterization of Co nanoparticles obtained by femtosecond pulsed laser deposition

We present a detailed study on the morphology and magnetic properties of Co nanostructures deposited onto oxidized Si substrates by femtosecond pulsed laser deposition. Generally, Co disks of nanometric dimensions are obtained just above the ablation threshold, with a size distribution characterized...

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Bibliographic Details
Authors: Cebollada, Alfonso, García-Martín, José Miguel, Clavero Pérez, César, Balcells Argemi, Lluis, Estradé, J., Arbiol, J., Peiró, F., Smith, C., Clarke, Roy, Martínez Rodríguez, Luis Javier, Huttel, Yves, Román, Eduardo H., Telling, N. D., Van der Laan, G.
Format: article
Publication Date:2009
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/11580
Online Access:http://hdl.handle.net/10261/11580
Access Level:Open access
Keyword:Cobalt
magnetic circular dichroism
Magnetic domains
Magnetic force microscopy
Nanostructured materials
Pulsed laser deposition
SQUIDs
Surface structure
Description
Summary:We present a detailed study on the morphology and magnetic properties of Co nanostructures deposited onto oxidized Si substrates by femtosecond pulsed laser deposition. Generally, Co disks of nanometric dimensions are obtained just above the ablation threshold, with a size distribution characterized by an increasingly larger number of disks as their size diminishes, and with a maximum disk size that depends on the laser power density. In Au/Co/Au structures, in-plane magnetic anisotropy is observed in all cases, with no indication of superparamagnetism regardless of the amount of material or the laser power density. Magnetic force microscopy observations show coexistence of single-domain and vortex states for the magnetic domain structure of the disks. Superconducting quantum interference device magnetometry and x-ray magnetic circular dichroism measurements point to saturation magnetization values lower than the bulk, probably due to partial oxidation of the Co resulting from incomplete coverage by the Au capping layer.