Currently, the shield-to-shield separation of a spin valve head cannot
be below about 800 , mainly due to sensor-to-lead shorting problems. This
problem has now been overcome by inserting a high permeability, high resistivity,
thin film shield on the top or bottom (or both) sides of the spin valve sensor.
A permeability greater than about 500 is required together with a resistivity about
5 times greater than that of the free layer and an MrT value for the
thin film shield that is 4 times greater than that of the free layer. Five embodiments
of the invention are described.
