Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with exchange-coupled side shield structure

A magnetoresistive sensor structure for sensing magnetically recorded data from a magnetic recording medium, the structure comprising:

• a substrate;
• a current-perpendicular-to-the-plane magnetoresistive (CPP-MR) sensor comprising a stack of layers including a ferromagnetic free layer on a central region of the substrate and having a front edge for facing a magnetic recording medium, a back edge recessed from the front edge, and two spaced-apart side edges;
• an exchange-coupled side shield structure on each of two side regions of the substrate adjacent said central region of the substrate, each exchange-coupled side shield structure comprising a first antiferromagnetic layer on the substrate and a side shield of magnetically permeable material on and exchange-coupled with said first antiferromagnetic layer, said side shield having its magnetization oriented generally parallel to said sensor front edge and generally parallel to the plane of said free layer and being formed of a material selected from NiFex, (NiFex)Moy and (NiFex)Cry, where the subscripts are in atomic percent, where x is greater than or equal to 1 and less than or equal to 25 and where y is greater than or equal to 1 and less than or equal to 8;
• an electrically insulating layer between each exchange-coupled side-shield structure and a sensor side edge;
• an exchange-coupled top shield structure comprising a top shield of magnetically permeable material on the sensor and the two exchange-coupled side shield structures and a second antiferromagnetic layer on the top shield, said top shield having its magnetization oriented generally parallel to the magnetization of each side shield.