Magnetoresistive sensor and fabrication method for a magnetoresistive sensor

A fabrication method for a magnetoresistive sensor, the fabrication method comprising:

• fabricating a layer stack of the magnetoresistive sensor, including:
• forming a reference layer having a fixed reference magnetization, wherein the fixed reference magnetization has a first magnetic orientation;
• forming a magnetically free system of a plurality of layers, wherein the magnetically free magnetization is variable in a presence of an external magnetic field, and wherein the magnetically free magnetization has a second magnetic orientation in a ground state,
• wherein the magnetically free system has two ferromagnetic layers and a magnesium oxide interlayer, wherein the two ferromagnetic layers include a first ferromagnetic layer and a second ferromagnetic layer, wherein the first ferromagnetic layer and the second ferromagnetic layer have parallel magnetic orientations corresponding to the second magnetic orientation, wherein the magnesium oxide interlayer is arranged between the two ferromagnetic layers and comprises only magnesium oxide, wherein the magnesium oxide interlayer couples the two ferromagnetic layers together by an interlayer exchange coupling (IEC) effect such that the two ferromagnetic layers function as a single sensor layer with the parallel magnetic orientations corresponding to the second magnetic orientation, and wherein a thickness of the magnesium oxide interlayer is manufactured at a fixed dimension that is set between 0.05 nm and 0.4 nm;
• and
• forming a barrier layer that is arranged between the reference layer and the magnetically free system and comprises magnesium oxide.