  Recent progress on theoretical predictions of ternary superhydrides and their
subsequent experimental confirmations have introduced us with a new generation
of superconductors, having the potential to realize the synthesis of the most
anticipated room temperature superconductors. Motivated by the recent high
pressure experiment on YH$_6$ and EuH$_6$, we have theoretically examined the
stability as well as superconductivity by mixing the two compounds. Here we
identified four phases capable of maintaining thermodynamic stability in the
pressure range of 150-300 GPa, namely $Fm\bar{3}m$-Y$_{3}$EuH$_{24}$,
$Cmmm$-YEuH$_{12}$, $Cmmm$-YEu$_{3}$H$_{24}$,$Immm$-YEu$_{3}$H$_{24}$. Among
them, only $Fm\bar{3}m$-Y$_{3}$EuH$_{24}$ can maintain dynamically stability in
the searched pressure range. The Allen-Dynes modified McMillan formula was used
to further check the superconductivity of this phase, and the results reveal
that the predicted superconducting transition temperature $T\rm_{c}$ of
Y$_{3}$EuH$_{24}$ is approaching 220 K at 200 GPa.
$Fm\bar{3}m$-Y$_{3}$EuH$_{24}$ has a nearly identical logarithmic average
phonon frequency $\omega_{log}$ to YH$_{6}$, but its electron-phonon coupling
(EPC) constant $\lambda$ is somewhat smaller than YH$_{6}$'s 2.56, resulting in
a lower ultimate $T_{c}$ value.
