Abstract: A sensor element is described having a substrate and a first magnetoresistive layered assemblage having at least locally a first strip having a first strip width, and a second magnetoresistive layered assemblage having at least locally a second strip having a second strip width different from the first strip width. A gradiometer assemblage is described having at least two gradiometer bridges which have magnetoresistive, at least locally strip-shaped, layered assemblages of this kind, the strips in the individual gradiometer bridges being of different widths. This sensor element or gradiometer assemblage is suitable in particular for measuring magnetic field gradients over at least five orders of magnitude at magnetic field strengths from 1 ?T to 30 mT, in particular from 1 ?T to 10 mT.