High moment wrap shields for magnetic read head to improve micro-magnetic read width

摘要

A magnetically stable, read sensor uses low-coercivity magnetic material without seed layers in side shields for longitudinal biasing in order to improve micro-magnetic read width of the sensor. The sensor is formed between an upper and lower shield and includes a symmetric pair of abutting side shields adjacent to the sides of the sensor. In one configuration the side shields are partially covered by a layer of high magnetic moment material that extends along a bottom surface and side surface of the side shields and is contiguous and conformal with the layer of insulating material, but does not cover the backside of the sensor. The high moment layer focuses flux at the sensor sides and also improves the micro-magnetic read width. The side shields include a multiplicity of horizontal ferromagnetic layers that are antiferromagnetically coupled to each other and magnetically coupled to the upper shield.

主权项

1. A shielded read sensor comprising:
a horizontal lower shield formed of magnetic material; a horizontal upper shield formed of magnetic material; a horizontally layered, patterned sensor formed centrally between said lower shield and said upper shield, wherein said patterned sensor has an upper surface and a lower surface and a planar ABS surface and a backside surface substantially parallel to said planar ABS surface and separated from said planar ABS surface by a distance d, and wherein said patterned sensor further includes horizontally opposed side surfaces and wherein said lower surface of said patterned sensor contacts an upper surface of said horizontal lower shield and wherein said upper surface of said patterned sensor contacts a lower surface of said upper shield; and wherein a layer of insulation uniformly, contiguously and conformally covers said opposed side surfaces and said backside surface of said patterned sensor and extends laterally over a portion of said upper surface of said lower shield that is laterally disposed to either side of said patterned sensor stack; and wherein a symmetrically disposed pair of horizontal side shields abut each side of said patterned sensor; wherein each of said horizontal side shields includes a multiplicity of horizontal magnetic layers; and wherein each of said side shields comprises a first magnetic layer that is a lowermost layer, a first antiferromagnetic (AFM) coupling layer formed on said first magnetic layer, a second magnetic layer, a second AFM coupling layer formed on said second magnetic layer, and a third magnetic layer that is an uppermost layer; wherein said first, second and third magnetic layers are magnetized, wherein said magnetization of said first magnetic layer is aligned anti-parallel to said magnetization of said second magnetic layer while a magnetization of said third magnetic layer is aligned anti-parallel to said magnetization of said second magnetic layer; wherein said uppermost magnetic layer of each of said pair of side shields has a horizontal upper surface that contacts said lower surface of said horizontal upper shield; and wherein said lowermost magnetic layer of each of said pair of side shields has a horizontal lower surface that contacts said layer of insulation that extends laterally over a portion of said upper surface of said lower shield; and wherein each of said pair of side shields has a side surface that includes lateral edges of said horizontal magnetic layers and wherein said lateral edges conformally abut and contact said layer of insulation that uniformly, contiguously and conformally covers said opposed side surfaces of said patterned sensor; whereby each of said pair of side shields is capable of being magnetically stabilized by a magnetic interaction with said horizontal upper and lower shields and wherein; no seed layers are utilized in the formation of said side shields; and wherein said patterned sensor is capable of being longitudinally biased and magnetically stabilized by magnetic interaction with said side shields, said top shield and said bottom shield.