  Like air flowing over a wing, optimizing the flow of electronic charge is
essential to the operation of nanoscale devices. Unfortunately, the delicate
interplay of charge, spin, and heat in complex devices has precluded detailed
imaging of charge flow. Here, we report on the visualization of intrinsic
charge current streamlines through yttrium iron garnet micromagnetic
heterostructures. Scanning photovoltage microscopy of precisely designed
devices leads to striking spatial patterns, with prominent photovoltage
features emerging in corners and narrow constrictions. These patterns, which
evolve continuously with rotation of an external magnetic field, enable rich
spatial mapping of fluid-like flow. Taking inspiration from aerodynamic Clark Y
airfoils, we engineer micromagnetic wing shaped devices, called electrofoils,
which allow us to precisely contort, compress and decompress flowlines of
electronic charge.120 (39) e2221815120
