  Controllable writing and deleting of nanoscale magnetic skyrmions are key
requirements for their use as information carriers for next-generation memory
and computing technologies. While several schemes have been proposed, they
require complex fabrication techniques or precisely tailored electrical inputs,
which limits their long-term scalability. Here we demonstrate an alternative
approach for writing and deleting skyrmions using conventional electrical
pulses within a simple, two-terminal wire geometry. X-ray microscopy
experiments and micromagnetic simulations establish the observed skyrmion
creation and annihilation as arising from Joule heating and Oersted field
effects of the current pulses, respectively. The unique characteristics of
these writing and deleting schemes, such as spatial and temporal selectivity,
together with the simplicity of the 2-terminal device architecture, provide a
flexible and scalable route to the viable applications of skyrmions.
