Scissor type magnetic sensor with high magnetic moment bias structure for reduced signal asymmetry

摘要

A scissor type magnetic sensor having a magnetic bias structure extending from the back edge of first and second magnetic free layers. The magnetic bias structure is constructed of a magnetic material having a high magnetic moment, such as NiFe with a high Fe content or CoFe. The high magnetic moment bias structure reduces magnetic signal asymmetry while also maintaining high signal amplitude.

主权项

1. A magnetic sensor, comprising:
first and second free magnetic layers that are anti-parallel coupled with one another by a non-magnetic anti-parallel coupling layer sandwiched between the first and second free magnetic layers, the first and second free magnetic layers each having a front edge located at a media facing surface and a back edge opposite the front edge; and a magnetic bias layer located adjacent to the back edge of the first and second free magnetic layers and extending in a direction away from the media facing surface, the magnetic bias layer comprising a material having a high magnetic moment; wherein the magnetic bias layer is formed entirely of NiFe having an Fe content greater than 40 atomic percent, but not greater than 60 atomic percent; and wherein the first and second free magnetic layers and the non-magnetic anti-parallel coupling layer have first and second laterally opposed sides, the magnetic sensor further comprising first and second soft magnetic side shield structures extending from each of the first and second sides of the first and second magnetic free layers and non-magnetic anti-parallel coupling layer.