Nanomagnetic logic: Demonstration of directed signal flow for field-coupled computing devices

In Nanomagnetic Logic (NML), computing operations are performed by non-volatile, field-coupled nanomagnets. For information propagation in nanomagnetic wires between logic gates, directed signal flow has to be implemented in the field-coupled devices. In this paper we present the solution for directed information propagation in a wire realized in NML with perpendicular magnetization. For the first time, non-reciprocal signal flow is experimentally demonstrated for field-coupled nanomagnets and homogeneous clocking fields. Micromagnetic simulations are performed and field-coupled nanomagnets are fabricated by focused ion beam (FIB) lithography and ion beam etching. Partial irradiation with a FIB is investigated to tailor the switching behavior of the nanomagnets. Three coupled nano-magnets in a wire are measured to verify the simulation results. Non-reciprocal field-coupling of the nanomagnets is proven by experiments within a nanomagnetic wire.