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@InProceedings{SubkhangulovMIHRARK:2015:FeOpEx,
               author = "Subkhangulov, R. and Mikhaylovskiy, R. and Ivanov, B. and 
                         Henriques, A. and Rappl, Paulo Henrique de Oliveira and Abramof, 
                         Eduardo and Rasing, T. and Kimel, A.",
          affiliation = "{University Nijmegen} and {University Nijmegen} and {Institute of 
                         Magnetism} and {Universidade de S{\~a}o Paulo (USP)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Radboud University 
                         Nijmegen} and {Radboud University Nijmegen}",
                title = "Femtosecond optical excitation of spin resonances in the easy 
                         plane antiferromagnet semiconductor EuTe",
                 year = "2015",
         organization = "International Conference on Magnetism, 20.",
             abstract = "Understanding laser-induced spin dynamics in magnetic materials is 
                         a cornerstone for highspeed spintronics and magnetic recording. 
                         Here we investigated the ultrafast spin dynamics in the model 
                         Heisenberg antiferromagnetic semiconductor EuTe. We employed a 
                         time-resolved all-optical pump-probe technique at a temperature of 
                         1.7 K and magnetic fields up to 70 kG applied in the plane of the 
                         sample. We demonstrate that the optically excited electrons from 
                         the 4f to 5d EuTe band trigger antiferromagnetic spin precession 
                         consisting of two modes, in accordance with the theoretical model 
                         for an easy plane antiferromagnet. Analyzing the efficiency of the 
                         excitation of the modes as a function of the applied magnetic 
                         field we found that the antiferromagnetic spin precession is 
                         induced by the ferromagnetic 5d- 4f exchange interaction, which is 
                         high in comparison with the antiferromagnetic f-f exchange. The 
                         d-f exchange in EuTe, in particular, gives rise to the isotropic 
                         magneto refractive effect. It is manifested as a modulation of the 
                         bandgap of EuTe at the antiferromagnetic resonance frequency and 
                         can be monitored by measuring the pump induced reflectivity 
                         changes in the probe beam. We found that the antiferromagnetic s 
                         precession is triggered at magnetic fields higher than that of the 
                         spin flop transition at ~1 kG, and lower than that of spin flip 
                         transition at ~70 kG. We found that at magnetic fields, 
                         corresponding to the crossing of the two modes, the amplitudes of 
                         both modes are strongly enhanced; meanwhile the damping is 
                         strongly suppressed. The amplitude enhancement can be explained by 
                         a weak coupling of the two antiferromagnetic modes, which can be 
                         due to a small non-collinearity of the external magnetic field to 
                         the sample plane. We show that the damping suppression can be 
                         explained by accounting possible modification of the damping by 
                         the 5d electrons.",
  conference-location = "Barcelona, Spain",
      conference-year = "5-10 July",
             language = "en",
        urlaccessdate = "05 dez. 2020"
}


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