A stator core or a rotor core for an electrical machine, the core comprising: a plurality of teeth separated by slots in a circumferential direction of the core, a plurality of lamination stacks arranged one after another in an axial direction of the core, and separated from each other in the axial direction by cooling ducts, each lamination stack comprising a plurality of laminations (70, 130) arranged one after another in the axial direction such that each pair of neighbouring laminations (70, 130) is in contact with each other, each lamination stack comprising among the plurality of laminations (70, 130) a plurality of regular laminations, each regular lamination comprising a plurality of regular lamination teeth separated by lamination slots in the circumferential direction to form respective regular tooth sections and slot sections when at least two regular laminations are stacked one after another in the axial direction, each lamination stack further comprising among the plurality of laminations (70, 130) a plurality of slit laminations, each slit lamination comprising a plurality of slit lamination teeth separated by lamination slots in the circumferential direction to form respective slit tooth sections and slot sections when at least two slit laminations are stacked one after another in the axial direction, each slit lamination tooth comprising at least one slit providing a discontinuity in the electrical conductivity of the lamination material, the at least one slit being configured to reduce eddy current losses at the respective slit lamination, characterized in that each lamination stack comprises at its each end in the axial direction at least one slit tooth section, and between the slit tooth sections in the axial direction at least one regular tooth section. a plurality of teeth separated by slots in a circumferential direction of the core, a plurality of lamination stacks arranged one after another in an axial direction of the core, and separated from each other in the axial direction by cooling ducts, each lamination stack comprising a plurality of laminations (70, 130) arranged one after another in the axial direction such that each pair of neighbouring laminations (70, 130) is in contact with each other, each lamination stack comprising among the plurality of laminations (70, 130) a plurality of regular laminations, each regular lamination comprising a plurality of regular lamination teeth separated by lamination slots in the circumferential direction to form respective regular tooth sections and slot sections when at least two regular laminations are stacked one after another in the axial direction, each lamination stack further comprising among the plurality of laminations (70, 130) a plurality of slit laminations, each slit lamination comprising a plurality of slit lamination teeth separated by lamination slots in the circumferential direction to form respective slit tooth sections and slot sections when at least two slit laminations are stacked one after another in the axial direction, each slit lamination tooth comprising at least one slit providing a discontinuity in the electrical conductivity of the lamination material, the at least one slit being configured to reduce eddy current losses at the respective slit lamination, characterized in that each lamination stack comprises at its each end in the axial direction at least one slit tooth section, and between the slit tooth sections in the axial direction at least one regular tooth section.