1. A device with adjustable resistance comprising: two magnetic elements (FM 1 , FM 2 ) separated by an insulating element or semi-conductor (I), the resistance of the device being dependent on the position of a magnetic wall in one of the magnetic elements (FM 1 ), the magnetic wall separating two areas of said magnetic element each having a separate homogeneous direction of magnetization, said device including means for moving the magnetic wall in said magnetic element (FM 1 ) by applying a spin-polarized electric current (i E ), such that the resistance of the device is adjustable in a continuous range of values.