Filmes de MnAs sobre GaAs e nanoestruturas de MnAs implantadas em GaAs

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

We have studied the structural and magnetic phase transition of MnAs in films epitaxially grown by MBE on GaAs (001) and GaAs (001) implanted samples with Mn and subsequent annealing. In the two kinds of samples the structural transition was studied by x-ray diffraction as a function of temperature. The results presented a continuous and smooth decrease in the average concentration of a MnAs, characterizing a transition with thermal hysteresis and coexistence of the a and b phases in a temperature range up to 40o C. This behavior differs from that one of the bulk MnAs that presents an abrupt and discontinuous transition. We investigated the magnetic transition on the films and its coupling with the structural one, by experiments in a SQUID magnetometer and magneto-optical Kerr effect. In the implanted samples we performed the Secondary Ion Mass Spectrometry (SIMS) and the Atomic Force Microscopy (AFM) to study the diffusion of Mn to the surface and the formation of superficial nanostructures. We also performed Grazing Incidence x-ray Diffraction (GID) to determinate the crystal orientation MnAs nanostructures with respect to the substrate. The morphological and compositional analysis of these nanostructures were estudied by high resolution Transmission Electron Microscopy (TEM) and Energy Dispersive x-ray Analysis (EDX)

ASSUNTO(S)

nanoestrutura spintronica filmes finos

ACESSO AO ARTIGO

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