Extraordinary Hall effect in thin magnetic films and its potential for sensors, memories and magnetic logic applications

We investigate the potential of the extraordinary Hall effect (EHE) in magnetic thin films with out-of-plane anisotropy for sensors, memories or logic applications. The scalability of EHE at decreasing lateral dimension has been first explored. In order for EHE to provide output voltage compatible with CMOS technology, it is shown that the longitudinal resistivity of the magnetic material must be considerably increased at decreasing size while keeping a large Hall angle. Then the EHE properties of various classes of materials with out-of-plane anisotropy ((Co/Pt) multilayers, FePt ordered alloys, rare-earth/transition metal alloys, CoSiOx and CoPtSiOx heterogeneous composites) are measured and compared in order to evaluate their potential for the envisioned applications. It is concluded that while EHE can readily be used for large devices (size > micrometres), no materials are yet available which offer suitable scalability towards the 22 nm microelectronic node.