On-chip Extraordinary Hall-effect sensors for characterization of nanomagnetic logic devices

Ferromagnetic Co/Pt films and single-domain magnets are characterized by various types of Extraordinary Hall-Effect (EHE) sensors. The magnetron sputtered multilayer films are annealed and measured in the temperature range of 22 °C ⩽ T ⩽ 75 °C. By focused ion beam (FIB) irradiation, the magnetic properties of the Co/Pt stack are tailored to define both the switching field and the geometry of nanomagnetic single domain dots. A submicron sized EHE-sensor for read-out of field-coupled computing devices is presented. The applied sensing structure is suitable to electrically probe the output states of field-coupled magnetic logic gates. Furthermore, it reveals details on the magnetic properties of submicron-scale single-domain dots and the main measured features are confirmed by micromagnetic simulations. A ‘split-current’ architecture is chosen, where Hall sensing takes place in a single lateral direction, in order to keep field-coupling to adjacent nanomagnets undisturbed. From angular measurements we conclude that the reversal mechanism of the FIB patterned magnetic dots is domain-wall driven. The sensor is a main component needed for integration of nanomagnetic computing units embedded into microelectronic systems.