A rotor of an electric machine has a circumferential surface and a permanent-magnet structure on the circumferential surface . A contour of the permanent-magnet structure has a stepped section with several steps, whereby each step has a first extension that is oriented essentially perpendicularly to the circumferential direction of the circumferential surface as well as a second extension that is oriented parallel to the circumferential direction and that connects the first extension to a first extension of an adjacent step. The first extension of a first step differs from the first extension of a second step that is adjacent to the first step and/or the second extension of a first step differs from the second extension of the second step.