Spin valve device with improved exchange layer defined track width and method of fabrication

Abstract

The present invention provides an exchange break to define the track width of a read head by selectively isolating an exchange coupling layer from an underlying ferromagnetic layer. In the preferred embodiment, the exchange break is provided over a portion of the free layer of a spin valve device so that it inhibits exchange coupling between an overlying portion of the exchange coupling layer and the underlying free layer to define an active region. It is preferred to form the exchange break of an electrically insulating material, to inhibit current shunting through the exchange break, and of a material that easily etches, to minimize inadvertent etching of the underlying free layer and to ensure complete removal of exchange break material when forming the exchange break from an exchange break layer. A reentrant profile photoresist structure may be used to define the exchange break and to define the exchange coupling layer. Drift portions of the exchange coupling layer, which typically form under the overhang of the photoresist and blur delineation of the active region, are separated from the underlying free layer by the exchange break, so that variations in thickness and in shifted material composition do not blur active region delineation. Because the width of the active region is defined by the exchange break, the present invention decouples the track width of the device from the geometry of the exchange coupling layer.