MAGNETIZATION CONTROLLED SUPERCONDUCTIVITY IN A FILM WITH MAGNETIC DOTS

We consider a superconducting film with a magnetic dots array (MDA) pl aced upon it. Magnetic moments of the dots are normal to the film and strong enough to create vortices in the superconducting film. Magnetic interaction between dots is negligible. Zero-field cooling leads to r andom magnetization of the MDA well above the superconducting temperat ure. With this cooling, the film is in a resistive state below the (ex pected) superconducting transition. Paradoxically, when field cooled, the film with MDA can be superconducting.