  Partially filled Landau levels host competing orders, with electron solids
prevailing close to integer fillings before giving way to fractional quantum
Hall liquids as the Landau level fills. Here, we report the observation of an
electron solid with noncolinear spin texture in monolayer graphene, consistent
with solidification of skyrmions---topological spin textures characterized by
quantized electrical charge. In electrical transport, electron solids reveal
themselves through a rapid metal-insulator transition in the bulk electrical
conductivity as the temperature is lowered, accompanied by the emergence of
strongly nonlinear dependence on the applied bias voltage. We probe the spin
texture of the solids using a modified Corbino geometry that allows
ferromagnetic magnons to be launched and detected. We find that magnon
transport is highly efficient when one Landau level is filled ($\nu=1$),
consistent with quantum Hall ferromagnetic spin polarization; however, even
minimal doping immediately quenches the the magnon signal while leaving the
vanishing low-temperature charge conductivity unchanged. Our results can be
understood by the formation of a solid of charged skyrmions near $\nu=1$, whose
noncolinear spin texture leads to rapid magnon decay. Data near fractional
fillings further shows evidence for several fractional skyrmion crystals,
suggesting that graphene hosts a vast and highly tunable landscape of coupled
spin and charge orders.
