INTECIN   20395
INSTITUTO DE TECNOLOGIAS Y CIENCIAS DE LA INGENIERIA "HILARIO FERNANDEZ LONG"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Role of Structural Defects of Cobalt Ferrite as Target on Magnetic Properties of FM/fm Systems Prepared by PLD Technique
Autor/es:
V. BILOVOL; L.G. PAMPILLO; RICARDO MARTÍNEZ GARCÍA; F.D. SACCONE
Lugar:
Sao Carlos
Reunión:
Conferencia; The 5th Latin American Conference on Metastable and Nanostructured Materials; 2012
Resumen:
A series of
bilayers of ferromagnet (FM)/ferrimagnet(fm) type was grown on Si (111)
substrate with Fe as FM and CoFe2O4 as fm, by means of
the Pulsed Laser Deposition technique (PLD). In order to investigate the role
of transferring the ?structural quality? of fm targets (CoFe2O4)
on magnetic properties of the films, we characterized magnetic properties of
the latter, in particular, exchange bias (EB) effect. The model proposed by
Nowak et al [1], successfully applied by them to a bilayer of the type
FM/AFM (antiferromagnetic), holds that EB field depends on defects present in
the volume part of the AFM layer.
Three different targets of cobalt ferrite were
prepared on the base of chemically synthesized nanoparticles, different
structural disorder was induced on each one by means of distinct thermal
treatments. The XRD technique shows clearly (111)-preferred orientation of CoFe2O4
layer. We observed that the sample prepared using CoFe2O4
nanoparticles synthesized at lowest temperature (and having in such a way the
most important structural defects) revealed the smallest value of coercive
field when measuring M vs H curve at room temperature. On the other hand, the
sample prepared using the cobalt ferrite nanoparticles with the least amount of
defects showed the highest value of coercive field. When the loops were
acquired at 20 K after field cooled at H = 3T, the highest EB field was found
for the sample prepared from the more structurally disordered target. In such a
way, we established that the model of Nowak is also valid for a
system with a ferrimagnetic (CoFe2O4) layer.