  Magnetic skyrmions, which are topological particle-like excitations in
ferromagnets, have attracted a lot of attention recently. Skyrmionics is an
attempt to use magnetic skyrmions as information carriers in next generation
spintronic devices. Proposals of manipulations and operations of skyrmions are
highly desired. Here, we show that the conversion, duplication and merging of
isolated skyrmions with different chirality and topology are possible all in
one system. We also demonstrate the conversion of a skyrmion into another form
of a skyrmion, i.e., a bimeron. We design spin logic gates such as the AND and
OR gates based on manipulations of skyrmions. These results provide important
guidelines for utilizing the topology of nanoscale spin textures as information
carriers in novel magnetic sensors and spin logic devices.
