MAGNETIC RECORDING DISK WITH ANTIFERROMAGNETICALLY-COUPLED MAGNETIC LAYER HAVING MULTIPLE HAVING MULTIPLE FERROMAGNETICALLY-COUPLED LOWER LAYERS

摘要

A magnetic recording disk has an antiferromagnetically-coupled (AFC) structure that has an upper ferromagnetic layer (UL), and a lower ferromagnetic layer structure formed of two ferromagnetically-coupled lower layers (LL 1 , LL 2 ). The UL is antiferromagnetically-coupled to the lower layer structure across an antiferromagnetically-coupling layer. LL 1 and LL 2 are ferromagnetically coupled across a ferromagnetic coupling layer so the magnetizations of LL 1 and LL 2 remain parallel in each remanent magnetic state, but are antiparallel to the magnetization of the UL in each remanent magnetic state. The UL has an Mrt greater than the sum of the Mrt values of LL 1 and LL 2.