Figure 2: Identifying regions of optimal NML signal propagation for pulsed clocking fields.

(a) The uniaxial (K_u) and biaxially (K_b) anisotropy energy (red circles and blue squares, respectively) as a function of nanomagnet length for 150-nm-wide notched nanomagnets calculated from an analytical model and OOMMF simulations. Inset: schematic energy diagram with respect to the magnetic orientation from the hard axis (θ=0), indicating the biaxial anisotropy-generated metastable state. (b) Average signal propagation distance in nanomagnet chains from the input magnet as a function of the nanomagnet length experimentally observed in two samples (red and blue squares) with MTXM. Error bars report the standard error of the mean. (c,d) Illustration and MTXM image of a chain of seven nanomagnets with their magnetization locked along the hard axis (along ŷ) after initialization. Pink lines distinguish individual nanomagnets in the chain. MTXM can resolve the antiparallel domains (parallel to the easy axis along ) in the notched region of the biaxially engineered nanomagnets. (e,f) Illustration and MTXM image of perfect signal propagation in a chain of 12 nanomagnets. Pink lines distinguish individual nanomagnets in the chain. The magnetization along the easy axis of neighbouring nanomagnets is oriented antiparallel along . In d and f, colour scales represent easy axis magnetization, and scale bars represent 1 μm. (g) Signal propagation distance of nanomagnet chains from the input magnet as a function of nanomagnet length calculated from OOMMF simulations for ideally initialized chains clocked at 0 K (black squares), 300 K (red circles) and chains initialized by a 3-ns clocking pulse at 300 K (blue triangles). Error bars report the standard error of the mean.