Method and test structure for determining magnetic domain switching field when fabricating patterned exchange biased magnetoresistive (MR) head

摘要

A method for determining through a test structure a longitudinal magnetic exchange field within a patterned exchange biased magnetoresistive (MR) sensor element. To practice the method, there is first provided a substrate. Formed upon the substrate is a patterned magnetoresistive (MR) layer which has a projected length upon the substrate and a projected width upon the substrate. There is formed at a pair of separated locations over the patterned magnetoresistive (MR) layer a pair of patterned conductor lead layers. The pair of patterned conductor lead layers is separated by a track width of the patterned magnetoresistive (MR) layer, where the track width is smaller than the projected width. There is also formed within the track width and upon the patterned magnetoresistive (MR) layer a minimum of one patterned anti- ferromagnetic layer separated from each patterned conductor lead layer within the pair of patterned conductor lead layers by a minimum of one unpinned width of the patterned magnetoresistive (MR) layer. The patterned magnetoresistive (MR) layer also has a minimum of one pinned width of the patterned magnetoresistive (MR) layer beneath the minimum of one patterned anti-ferromagnetic layer. The projected length, the unpinned width and the pinned width of the patterned magnetoresistive (MR) layer are chosen such that the magnetic domains within the unpinned width and the pinned width are coupled such that they switch jointly in an externally applied magnetic field. Finally, there is measured through the patterned conductor lead layers a resistance change within the patterned magnetoresistive (MR) layer when the patterned magnetoresistive (MR) layer is exposed to the externally applied magnetic field. The invention also contemplates the test structure through which the method of the invention is practiced.