  We study the perpendicular transport characteristics of small
superconductor/ferromagnetic insulator/superconductor
(YBa$_2$Cu$_3$O$_{7-x}$/LaMnO$_{3+\delta}$/YBa$_2$Cu$_3$O$_{7-x}$) tunnel
junctions. At a large bias voltage $V\sim 1$ V we observe a step-like onset of
excess current that occurs below the superconducting transition temperature
$T<T_c$ and is easily suppressed by a magnetic field. The phenomenon is
attributed to a novel type of the superconducting proximity effect of
non-equilibrium electrons injected into the conduction band of the
ferromagnetic insulator via a Fowler-Nordheim tunneling process. The occurrence
of a strongly non-equilibrium population is confirmed by the detection of
photon emission at large bias voltage. Since the conduction band in our
ferromagnetic insulator is strongly spin polarized, the long-range (20 nm) of
the observed proximity effect provides evidence for an unconventional
spin-triplet superconducting state.
