  Ferromagnetism and superconductivity are generally considered to be
antagonistic phenomena in condensed matter physics. Here, we theoretically
study the interplay between the ferromagnetic and superconducting orders in a
recent discovered monolayered CoSb superconductor with an orthorhombic symmetry
and net magnetization, and demonstrate the pairing symmetry of CoSb as a
candidate of non-unitary superconductor with time-reversal symmetry breaking.
By performing the group theory analysis and the first-principles calculations,
the superconducting order parameter is suggested to be a triplet pairing with
the irreducible representation of $^3B_{2u}$, which displays intriguing nodal
points and non-zero periodic modulation of Cooper pair spin polarization on the
Fermi surface topologies. These findings not only provide a significant
theoretical insight into the coexistence of superconductivity and
ferromagnetism, but also reveal the exotic spin polarized Cooper pairing driven
by ferromagnetic spin fluctuations in a triplet superconductor.
