Magnetic field induced absorption in Pb xEu1-xTe magnetic semiconductors

• Autor(a) principal: Hanamoto,L. K.
• Data de Publicação: 2004
• Outros Autores: Henriques,A. B., Rappl,P. H. de Oliveira, Oliveira,N. F., Ueta,A. Y., Abramof,E.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Physics
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332004000400044

We report an investigation of the optical absorption spectrum, using non-polarized light, in Pb xEu1-xTe, x=0 and x=0.095, epitaxial thick layers grown by molecular beam epitaxy (MBE). The absorption edge is described by a broad band, due to the electronic transitions from the 4f7 of Eu2+ to the states in 4f6 5d configuration, as seen previously in bulk Eu chalcogenides. When a magnetic field is applied, a narrow absorption band (full width ~50 meV) emerges from the broad one. The energy of this absorption peak red shifts when the magnetic field increases, and reaches saturation when the Eu2+ attain ferromagnetic arrangement. This behaviour can be described by a localized excitation model with d - f exchange interaction.