Magnetoentropic Signatures in Skyrmion Crystals: A Pathway to Magnetic Cooling

We present a theoretical investigation of the magnetoentropic signatures associated with various skyrmion crystal phases, including Néel, Bloch, and anti-skyrmions in both two-dimensional and three-dimensional systems. Using Monte Carlo simulations based on spin Hamiltonians, we calculate the magnetic entropy change (ΔSₘ) under different types of Dzyaloshinskii-Moriya interactions responsible for skyrmion formation. Phase mapping of ΔSₘ as a function of temperature and magnetic field, with skyrmion number (Nₛₖ), reveals a weak first-order transition and a sign change in ΔSₘ upon entering the skyrmion crystal phase, consistent with experimental observations. Notably, we find that the fractional entropy change from the ferromagnetic to the skyrmion crystal phase is significantly larger than that observed in the conventional paramagnetic-to-ferromagnetic transition, highlighting the enhanced cooling potential of skyrmion crystals that could significantly enhance magnetic cooling.