  We have investigated the magnetic and magnetocaloric properties of
EuHo$_2$O$_4$ and EuDy$_2$O$_4$ by magnetization and heat capacity measurements
down to 2 K. These compounds undergo a field-induced antiferromagnetic to
ferromagnetic transition and exhibit a huge entropy change. For a field change
of 0-8 T, the maximum magnetic entropy and adiabatic temperature changes are 30
(25) J kg$^{-1}$ K$^{-1}$ and 12.7 (16) K, respectively and the corresponding
value of refrigerant capacity is 540 (415) J kg$^{-1}$ for EuHo$_2$O$_4$
(EuDy$_2$O$_4$). These magnetocaloric parameters also remain large down to
lowest temperature measured and are even larger than that for some of the
potential magnetic refrigerants reported in the same temperature range for a
moderate field change. Moreover, these materials are highly insulating and
exhibit no thermal and field hysteresis, fulfilling the necessary conditions
for a good magnetic refrigerant in the low-temperature region.
