Magnetic skyrmion shape manipulation by perpendicular magnetic anisotropy excitation within geometrically confined nanostructures

•Skyrmion shape can act as an additional degree of freedom.•High frequency resonance modes of skyrmion excited by PMA possess shape deformation.•Excitation frequency, amplitude and geometric confinement affect deformation modes.•Phase diagram based on driving factors of shape deformation phenomenon.•Relationship between deformation modes and driving factors.