Read head having one or more antiferromagnetic layers below soft bias side shields, and related methods

A read head for magnetic storage devices, comprising:

• a lower shield;
• an upper shield;
• one or more lower leads disposed between the lower shield and the upper shield;
• a plurality of upper leads disposed above the one or more lower leads along a downtrack direction, wherein each of the plurality of upper leads and each of the one or more lower leads is nonmagnetic and conductive;
• a plurality of read sensors disposed between the one or more lower leads and the plurality of upper leads, wherein a buffer layer of each read sensor is disposed at a first distance relative to the lower shield, a cap layer of each read sensor is disposed at a second distance relative to the upper shield that is substantially equal to the first distance, and each read sensor of the plurality of read sensors comprises a multilayer structure, the multilayer structure comprising:
• a first antiferromagnetic (AFM) layer, and
• a free layer;
• a plurality of soft bias side shields disposed between and outwardly of the plurality of read sensors;
• and
• a plurality of second AFM layers disposed between the lower shield and the plurality of soft bias side shields.

A method of forming a read head for magnetic storage devices, comprising:

• forming a lower shield;
• forming one or more lower leads above the lower shield;
• forming a multilayer structure above the one or more lower leads, the multilayer structure comprising:
• a first antiferromagnetic (AFM) layer,
• a free layer, and
• a buffer layer disposed between the first AFM layer and the one or more lower leads;
• removing sections of the multilayer structure to form a plurality of read sensors that each comprise the multilayer structure;
• forming a plurality of first insulation layers between and outwardly of the plurality of read sensors;
• forming a plurality of second AFM layers above the plurality of first insulation layers;
• forming a plurality of soft bias side shields among the plurality of read sensors and above the plurality of second AFM layers, wherein the plurality of second AFM layers are disposed between the one or more lower leads and the plurality of soft bias side shields;
• forming a plurality of upper leads above the one or more lower leads along a downtrack direction, wherein each of the one or more lower leads and each of the plurality of upper leads is conductive, wherein the plurality of read sensors are disposed between the one or more lower leads and the plurality of upper leads;
• and
• forming an upper shield, wherein the one or more lower leads are disposed between the lower shield and the upper shield.