Magnetization Controlled Superconductivity in a Film with Magnetic Dots

TL;DR

This paper investigates how a magnetic dots array on a superconducting film can induce and control superconductivity, revealing that an external magnetic field can paradoxically enhance superconductivity in the system.

Contribution

It introduces a novel system where magnetic dots influence superconductivity, demonstrating the counterintuitive effect of magnetic field on the superconducting state.

Findings

Random magnetization of dots causes resistive state at zero field.

Finite magnetic field restores superconductivity in the system.

Magnetic interactions between dots are negligible.

Abstract

We consider a superconducting film with Magnetic Dots Array (MDA) placed on it. Magnetic moments of these dots are supposed to be normal to the film and strong enough to create vortices in the superconducting film. Magnetic interaction between dots is negligible. Below the superconducting transition temperature of the film in zero magnetic field the MDA with randomly magnetized dots produces resistive state of the film. Paradoxically, in a finite magnetic field the film with MDA is superconductive.