Figure 3: Observation of signal propagation in an NML chain by dipolar coupling.
From: Sub-nanosecond signal propagation in anisotropy-engineered nanomagnetic logic chains
(a) Photoelectron intensity count for an image containing the Au wire versus time delay. (b) Averaged TR XMCD-PEEM images of a nanomagnet chain at various time delays from 1 to 4 ns compared with a 1-μm scale bar. The chain demonstrates behaviour that suggests dipolar coupling is switching magnets sequentially from the hard axis (along ŷ) to an antiparallel configuration (black and white contrast) on the easy axis (along 
) at fast timescales on the order of 100 ps. Signal propagation from the third nanomagnet to the eighth nanomagnet driven by dipolar coupling (emphasized in the yellow region) is observed between images 1.4 and 1.8 ns. Pink lines distinguish individual nanomagnets in the chain. (c) An interpretation of the switching events are observed in b. Red indicates magnets that are either in their metastable state after clocking or indistinguishable due to contrast greying. Black and white indicate magnets that have oriented along the easy axis 
in opposite directions, respectively. Signal propagation from the third nanomagnet to the eighth nanomagnet driven by dipolar coupling (emphasized in the blue region) is observed between images 1.4 and 1.8 ns. Pink lines distinguish individual nanomagnets in the chain.
