Interplay between interfacial Dzyaloshinskii-Moriya interaction and magnetic anisotropy in 4d transition metal multilayers for skyrmion nucleation

Skyrmions refer to small swirling spin structures that emerge in ferromagnetic materials and show promising features to be used as a 'bit' of information in future spintronic devices. Our research explores the possibility of nucleating skyrmions in X-Fe/Ir(111) multilayer nano-structure where, X is one of the 4d transition metals, such as, Pd, Rh, Ru, Mo and Nb. The resulting final state is determined by the competition between the frustrated exchange interaction, primarily contributed by the top 4d transition metal layer, and the Dzyaloshinskii-Moriya interactions induced significantly by the 5d heavy metal Ir(111) layer. We apply a perpendicular dc magnetic field to the nano-structure and observe gradual phase transformation from the spin spiral ground state to a stable relaxed state of nano-scale skyrmions. A proper choice of magnetic anisotropy and interfacial Dzyaloshinskii-Moriya interaction leads to a range of external magnetic fields essential for the existence and stability of skyrmions. By raising the temperature, we assess the thermal stability of the nucleated skyrmions to evaluate their potential as information carriers in future spintronic devices.