  Nanomagnetic logic is an energy efficient computing architecture that relies
on the dipole field coupling of neighboring magnets to transmit and process
binary information. In this architecture, nanomagnet chains act as local
interconnects. To assess the merits of this technology, the speed and
reliability of magnetic signal transmission along these chains must be
experimentally determined. In this work, time-resolved pump-probe x-ray
photo-emission electron microscopy is used to observe magnetic signal
transmission along a chain of nanomagnets. We resolve successive error-free
switching events in a single nanomagnet chain at speeds on the order of 100 ps
per nanomagnet, consistent with predictions based on micromagnetic modeling.
Errors which disrupt transmission are also observed. We discuss the nature of
these errors, and approaches for achieving reliable operation.
