UC San Diego

A thin superconducting/ferromagnetic heterostructure was constructed for which it was found that the collective pinning of Abrikosov vortices can be induced or prevented depending on the ordering of a ferromagnetic dot array. Arrays in the magnetic vortex state will induce flux pinning if uniformly polarized, but a demagnetized, disordered array will not have collective commensurability with the flux lattice. The system also exhibits field- induced superconductivity as a byproduct of the interaction between magnetic vortex stray fields and penetrating flux quanta