In a read-write head, the shields can serve as magnetic flux conductors
for external fields, so that they direct a certain amount of flux into
the recording medium. This problem has been overcome by the addition to
the shields of a pair of tabs located at the edges closest to the ABS.
These tabs serve to prevent flux concentrating at the edges so that
horizontal fields at these edges are significantly reduced. Said tabs
need to have aspect ratios of at least 2 and may be either triangular or
rectangular in shape. Alternatively, the tabs may be omitted and,
instead, outer portions of the shield's lower edge may be shaped so as to
slope upwards away from the ABS.