@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 = "26 abr. 2024"
}