Patent ID: 7342396

Claim:
A device for sensing a magnetic field, wherein it comprises a closed superconducting pick-up loop having a path width (d) etched out of a single layer superconducting thin film of thickness (e 1 ), and provided with a constriction having a width (w) of narrow dimension smaller than said path width (d), said closed superconducting pick-up loop constituting a flux-to-field transformer (FFDT), and wherein at least one magnetoresistive element is placed on top of or below said superconducting thin film, is isolated from said superconducting thin film by a thin insulating layer of thickness (e 4 ) smaller than said width (w), and is located so that an active part of the magnetoresistive element is at the location of the constriction and has a width (W GMR ) equal to or less than the width (w) of the constriction, the active part of the magnetoresistive element being oriented so that the bias current in said active part is directed essentially along the constriction, orthogonally to the width (w) of narrow dimension.