Formação de nanoestruturas magneticas por aquecimento Joule

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

In this thesis, we discuss the processes of formation and control of magnetic nanostructures in binary alloys of composition Cu90 Co10 and Cu85 Co15, and in the amorphous alloy of composition Fe86 Zr7 Cu1 B6 through thermal annealing using the Joule heating technique. We present two diferent ways to control the Joule heating: by directly applying the annealing current, and through linearly varying the applied current. Also, we discuss the effects of the nanostructures on the magnetic properties of the above mentioned materials always stressing the importance of these properties for technical applications. In particular, we studied, in detail, the effect of the grain size distribution and the interaction between grains. The conclusions are based on structural (X-ray diraction, and transmission electron microscopy), and magnetic (hysteresis curves, magnetotransport, and AC susceptibility) measurements. We also performed numerical simulations using existing models and new models developed in our group

ASSUNTO(S)

materiais granulados nanoparticulas fenomenos de relaxação magnetismo

ACESSO AO ARTIGO

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