Single Chiral Skyrmions in Ultrathin Magnetic Films

The stability and sizes of chiral skyrmions in ultrathin magnetic films are calculated accounting for the isotropic exchange, Dzyaloshinskii–Moriya exchange interaction (DMI), and out-of-plane magnetic anisotropy within micromagnetic approach. Bloch skyrmions in ultrathin magnetic films with B20 cubic crystal structure (MnSi, FeGe) and Neel skyrmions in ultrathin films and multilayers Co/X (X = Ir, Pd, Pt) are considered. The generalized DeBonte ansatz is used to describe the inhomogeneous skyrmion magnetization. The single skyrmion metastability/instability area, skyrmion radius, and skyrmion width are found analytically as a function of DMI strength [Formula: see text]. It is shown that the single chiral skyrmions are metastable in infinite magnetic films below a critical value of DMI [Formula: see text] , and do not exist at [Formula: see text]. The calculated skyrmion radius increases as [Formula: see text] increases and diverges at [Formula: see text] , whereas the skyrmion width increases monotonically as [Formula: see text] increases up to [Formula: see text] without any singularities. The calculated skyrmion width is essentially smaller than the one calculated within the generalized domain wall model.