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Magnetic Nanoparticle Aggregation States in Ag100-xFex Cosputtered Granular Films Investigated by Magnetic and Magnetotransport Measurements

Published online by Cambridge University Press:  01 February 2011

Paolo Allia
Affiliation:
Physics Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, I- 1029 Torino, Italy
Federica Celegato
Affiliation:
Physics Department, Politecnico di Torino, Corso Duca degli Abruzzi 24, I- 1029 Torino, Italy
Marco Coisson
Affiliation:
Materials Department, IEN Galileo Ferraris, Strada delle Cacce 91, I-10135 Torino, Italy
Paola Tiberto
Affiliation:
Materials Department, IEN Galileo Ferraris, Strada delle Cacce 91, I-10135 Torino, Italy
Franco Vinai
Affiliation:
Materials Department, IEN Galileo Ferraris, Strada delle Cacce 91, I-10135 Torino, Italy
Federico Spizzo
Affiliation:
Physics Department, Universitä di Ferrara, Via Paradiso 12, I-44100 Ferrara, Italy
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Abstract

Magnetoresistance and.magnetization measurements have been performed on nanogranular, cosputtered Ag100-xFex films (x= 10 to 30) in the 4 K – 300 K temperature interval. The analysis reveals that the films with x ≤ 14 are interacting superparamagnets, characterized by a magnetic correlation length of the order of the electronic mean free path λ. Films with x ≥ 26 behave as concentrated magnets with strong competing interactions among magnetic moments (frustrated ferromagnets) and magnetic correlation length much larger than λ.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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