Narrow track technologies for shielded MR heads are discussed in terms
of off-track performance and increased head output. Permanent magnet
bias heads are increasingly superior to exchange coupling bias heads a
s tracks become narrower, because of the excellent off-track performan
ce of the permanent magnet type, Increasing the sense current is one w
ay to increase head output, However, the current increase raises the t
emperature of the MR element and degrades performance, An analysis of
the thermal behavior of the shielded MR head shows that increasing the
thermal conduction of the shield and gap layers, which are the main s
ources of heat radiation, and improving the crystalline properties of
the Ni-Fe film effectively suppress the rise in temperature of the MR
element.