Vortex superlattices

Spin-transfer torque and current-induced vortex superlattices in nanomagnets.
Oleksii M. Volkov, Volodymyr P. Kravchuk, Denis D. Sheka, and Yuri Gaididei
Phys. Rev. B 84, 052404 (2011)

Dependence of critical current J1 onthe nanodisk thickness for different disk diameters.