  Infrared reflectivity and time-domain terahertz transmission spectra of
EuTiO3 ceramics revealed a polar optic phonon at 6 - 300K, whose softening is
fully responsible for the recently observed quantum paraelectric behaviour.
Even if our EuTiO3 ceramics show lower permittivity than the single crystal due
to a reduced density and/or small amount of secondary pyrochlore Eu2Ti2O7
phase, we confirmed the magnetic field dependence of the permittivity, also
slightly smaller than in single crystal. Attempt to reveal the soft phonon
dependence at 1.8K on the magnetic field up to 13T remained below the accuracy
of our infrared reflectivity experiment.
