@InProceedings{HenriquesGalDíaRapAbr:2007:ExInEf,
               author = "Henriques, A. B. and Galgano, G. D. and D{\'{\i}}az, B. and 
                         Rappl, Paulo Henrique de Oliveira and Abramof, Eduardo",
          affiliation = "Instituto de F{\'{\i}}sica, Universidade de S{\~a}o Paulo and 
                         Instituto de F{\'{\i}}sica, Universidade de S{\~a}o Paulo and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Exchange Interaction Effects on the Optical Properties of 
                         EuxPb1\−xTe",
                 year = "2007",
                pages = "1233--1234",
         organization = "AIP Conference Proceedings.",
             abstract = "We measured the absorption band-edge in EuxPb1\−xTe in the 
                         ferromagnetic order induced by an external magnetic field (Faraday 
                         configuration). A narrow dichroic line, superimposed on a rising 
                         monotonous background, describes the spectrum. Here we examine if 
                         this line could be associated to an excitonic character of the 
                         electronic transition. Measurements of the absorption line width 
                         dependence on x (the molar fraction of Eu) allowed us to obtain an 
                         estimate for the characteristic radius of the excited wave 
                         function, and hence of the hypothetical exciton binding energy, 
                         which is found to be ~120 meV. When the magnetic field is removed, 
                         anti-ferromagnetic order is restored, and the absorption intensity 
                         decreases by more than one order of magnitude. Such a large change 
                         in the absorption cannot be explained in the framework of the 
                         excitonic absorption model.",
                  doi = "10.1063/1.2730345",
                  url = "http://dx.doi.org/10.1063/1.2730345",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
               volume = "893",
        urlaccessdate = "02 maio 2024"
}