Core slider for magnetic disk, having opposed recesses defining narrow final track which determines nominal magnetic gap width

A head core slider for a magnetic disk, including a slider body portion having an air bearing surface extending in a direction of length thereof, a core portion adjacent one of lengthwise opposite ends of the air bearing surface, said core portion having a magnetic gap which is open in a track surface which is at substantially the same height as said air bearing surface, said magnetic gap having a depth in a direction perpendicular to said air bearing surface, comprising:

• glass bodies having upper surfaces at the same height as said track surface and defining opposite edges of a track zone which extends across said magnetic gap in the direction of length of said air bearing surface and which has a first length and a first width, said first width being smaller than the width of said core portion, each of said glass bodies having a first depth larger than said depth of said magnetic gap;
• and
• means for defining a pair of opposed track width-defining recesses formed in said zone adjacent to said magnetic gap and defining an effective track which extends across said magnetic gap in said direction of length, said effective track having a second length and a second width which are smaller than said first length and width, respectively, said second width determining a nominal width of said magnetic gap, each of said recesses being open in said track surface and exposed to atmosphere, each of said recesses having a second depth which is smaller than said first depth of said glass bodies and larger than the depth of said magnetic gap, whereby said recesses prevent strain in said effective track, which strain would otherwise result from presence of glass material adjacent said effective track.