MTJ sensoring including domain stable free layer

A method to measure an electric current, comprising: providing a pair of conductive wires having corresponding first and second ends, said pair of wires being disposed so as to be equidistant over their full extents, said corresponding first ends being electrically connected to each other; placing, on each of said wires, a magnetic sensor having top and bottom leads between which a voltage drop occurs in the presence of a magnetic field, each such sensor having a free layer that further comprises a plurality of ferromagnetic elements and a reference layer that further comprises a plurality of ferromagnetic elements having pinned magnetizations, each of said elements having, in plan view, an aspect ratio of at least 1.2 and a length dimension of at most 1 micron whereby each such free layer is domain stable in the presence of a magnetic field, each of said pinned magnetizations being in a direction that is perpendicular to said length direction; passing said current between said corresponding second ends, thereby generating a magnetic field whose direction is different relative to each of the sensors whereby said sensors generate voltage drops whose magnitudes differ from one another; measuring said difference in magnitude between said voltage drops; and thereby deriving a value for said electric current.