The optical absorption spectrum of EuTe epitaxial layers grown by molecular beam epitaxy was studied at low temperatures and high magnetic fields, using circularly polarized light. At high magnetic fields a narrow line (width 41 meV) emerges at the low energy side of the absorption threshold. The line shows a huge displacement with magnetic field and is attributed to a magnetic exciton. The emergence of this line has a strong effect on the Faraday rotation, which becomes strongly non-linear.
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