  High tunability of two dimensional magnetic materials (by strain, gating,
heterostructuring or otherwise) provides unique conditions for studying
versatile magnetic properties and controlling emergent magnetic phases.
Expanding the scope of achievable magnetic phenomena in such materials is
important for both fundamental and technological advances. Here we perform
atomistic spin-dynamics simulations to explore the (chiral) magnetic phases of
atomic monolayers in the limit of suppressed first-neighbors exchange
interaction. We report the rich phase diagram of exotic magnetic
configurations, obtained for both square and honeycomb lattice symmetries,
comprising coexistence of ferromagnetic and antiferromagnetic spin-cycloids, as
well as multiple types of magnetic skyrmions. We perform a minimum-energy path
analysis for the skyrmion collapse to evaluate the stability of such
topological objects, and reveal that magnetic monolayers could be good
candidates to host the antiferromagnetic skyrmions that are experimentally
evasive to date.
