•Steady vortex gyrotropic motion in a confined nanocontact structure.•Smaller nanocontact and bigger dot aspect ratios correspond to broader current range.•Smaller nanocontact corresponds to wider adjustable range of the frequency.We studied the steady vortex gyrotropic motion in a Permalloy nanodot driven by an out-of-plane spin-polarized current which is injected through a nanocontact. First, we calculated the current density range in which the vortex steady motion can exist. It is found that both the nanocontact dimensions and dot aspect ratios have influence on it. Then the orbital radius and oscillation frequency of the steady motion in the plane of current density and nanocontact radius were diagramed. It indicated that smaller nanocontact corresponds to wider frequency range.

•We study the gyrotropic motion of a vortex in a double-nanocontacts system.•The VC frequency shows zigzag variation with time or appears a peak depend on the current direction.•The forces generated by the Oersted fields mainly attribute to the frequency changes.We studied the gyrotropic motion of a vortex in a double-contacts system, where two spin-polarized out-of-plane dc currents were injected into a nanodisk through a centered nanocontact and an off-centered nanocontact, respectively. Driven by the two currents, the orbit of vortex core distorts. Moreover, the gyrotropic frequency shows zigzag variation with time when the off-centered current passes from −z to +z-axis, and a peak appears when the off-centered current passes from +z to −z-axis. We analyzed the forces acting on the vortex core, and found that the changes of frequency mainly attribute to the forces generated by the Oersted fields arising from the two currents.

•We study the gyrotropic motion of a vortex in a double-nanocontacts system.•The VC frequency shows zigzag variation with time or appears a peak depend on the current direction.•The forces generated by the Oersted fields mainly attribute to the frequency changes.We studied the gyrotropic motion of a vortex in a double-contacts system, where two spin-polarized out-of-plane dc currents were injected into a nanodisk through a centered nanocontact and an off-centered nanocontact, respectively. Driven by the two currents, the orbit of vortex core distorts. Moreover, the gyrotropic frequency shows zigzag variation with time when the off-centered current passes from −z to +z-axis, and a peak appears when the off-centered current passes from +z to −z-axis. We analyzed the forces acting on the vortex core, and found that the changes of frequency mainly attribute to the forces generated by the Oersted fields arising from the two currents.

•We study the field-driven evolution of the magnetic state in a nanodisk with DMI.•The phase diagram in the perpendicular field-magnetic anisotropy plane is obtained.•The typical evolution of magnetic states for different anisotropy constant are shown.We study the effect of magnetic anisotropy on the field-driven evolution of magnetic structure in a nanodisk with existence of Dzyaloshinskii-Moriya interaction by using micromagnetic simulations. We obtain the phase diagram of magnetic state in the magnetic field-magnetic anisotropy constant (Hz-K) plane. It is found that target skyrmion can stably exist at zero external magnetic field when the magnetic anisotropy constant changing in a large range. The evolution of magnetic state with the perpendicular magnetic field strongly depends on the magnetic anisotropy constant.