Transverse bias strength enhancement in dual free layer tunnel magnetoresistive read heads

摘要

The present disclosure generally related to read heads having dual free layer (DFL) sensors. The DFL sensor and has a surface at the media facing surface (MFS). Behind the DFL sensor away from the MFS, is a rear hard bias (RHB) structure. The RHB structure is disposed between the shields as well. In between the DFL sensor and the RHB structure is insulating material. The insulating material is a multilayer structure. A first layer of the multilayer structure is composed of the same material as the tunnel magnetoresistive barrier layer, such as MgO, and is disposed adjacent the DFL sensor, yet spaced from the RHB structure. A second layer of the multilayer structure is a different insulating layer that is disposed adjacent the RHB structure, yet spaced from the DFL sensor. The multilayer structure helps improve areal density without degrading head stability and performance reliability by maintaining RHB coercivity.