  Strongly-interacting nanomagnetic arrays are crucial across an ever-growing
suite of technologies. Spanning neuromorphic computing, control over
superconducting vortices and reconfigurable magnonics, the utility and appeal
of these arrays lies in their vast range of distinct, stable magnetisation
states. Different states exhibit different functional behaviours, making
precise, reconfigurable state control an essential cornerstone of such systems.
However, few existing methodologies may reverse an arbitrary array element, and
even fewer may do so under electrical control, vital for device integration.
  We demonstrate selective, reconfigurable magnetic reversal of ferromagnetic
nanoislands via current-driven motion of a transverse domain wall in an
adjacent nanowire. The reversal technique operates under all-electrical control
with no reliance on external magnetic fields, rendering it highly suitable for
device integration across a host of magnonic, spintronic and neuromorphic logic
architectures. Here, the reversal technique is leveraged to realise two fully
solid-state reconfigurable magnonic crystals, offering magnonic gating,
filtering, transistor-like switching and peak-shifting without reliance on
global magnetic fields.
