A thin film magnetic head includes a three-step configuration including deep
and
shallow groove surfaces, a super shallow groove surface, and an air bearing surface,
and also, island-shaped center rail is provided in the center of the air outflow
end of the disk-facing air bearing surface having a boundary on the surface of
base alumina between a head element portion and a substrate, without including
the surface of the substrate. Further, by providing in the surface of the substrate
the super shallow groove surface shallower than a shallow groove surface, an alumina
recession between the surface of the substrate and the head element portion, produced
in a shallow dual step sub ambient slider, can be eliminated. Magnetic spacing
between the head of the head element portion and the magnetic layer of the disk
can be thereby reduced.