Magneto-resistive detector with scanning bubble domain

Claim 1

A magnetoresistive sensing device for selectively reading information-representing magnetization patterns at a plurality of separate information positions, comprising: a single elongate magneto-resistive sensing element disposed in said magnetization patterns adjacent said information positions; a plate of magnetizable material having uniaxial anisotropy and including a magnetic bubble domain transport track, which track is disposed substantially parallel to said sensing element; means which move a first magnetic bubble domain along said track to scan a plurality of successive locations, each of said locations being disposed adjacent a discrete area of said sensing element which is coupled to the magnetic field at one of said information positions, the relative size of said first magnetic bubble domain and the disposition of said locations being such that the magnetic field associated with said first bubble domain influences the resistance of only a corresponding one of said discrete areas from each of said locations; and means connected to said sensing element which function to detect resistance variations in said sensing element and which distinguish between resistance variations produced in the discrete area which is influenced by the field of said first bubble domain and resistance variations produced in the remainder of said sensing element.