Thin laminated single pole perpendicular write head

摘要

Single write poles tend to large shape anisotropy which results in a very large remnant field when not actually writing. This has now been eliminated by giving the write pole the form of a three layer laminate in which two ferromagnetic layers are separated by a non-magnetic or antiferromagnetic coupling layer. Strong magnetostatic coupling between the outer layers causes their magnetization directions to automatically be antiparallel to one another, unless overcome by the more powerful write field, leaving the structure with a low net magnetic moment. The thickness of the middle layer must be carefully controlled.