In all of the embodiments disclosed herein, seed layer 11 may be comprised of one or more of NiCr, Ta, Ru, Ti, TaN, Cu, Mg, or other elements or alloys typically employed to promote a smooth and uniform grain structure in overlying p-MTJ layers. Within SyAP layer 15, the AFC layer 13 is preferably Ru with a thickness of 4, 9, or 14 Angstroms to provide optimal AF coupling between AP1 layer 14 and AP2 layer 12. Optionally, Rh or Ir may serve as the AFC layer. Each of the AP1 and AP2 layers may be comprised of one or more of Co, Fe, and Ni, or an alloy thereof with B. In other embodiments, one or both of the AP1 and AP2 layers may be a laminated stack with inherent PMA such as (Co/Ni)_n, (CoFe/Ni)_n, (Co/NiFe)_n, (Co/Pt)_n, (Co/Pd)_n, or the like where n is the lamination number. Furthermore, a transitional layer such as CoFeB may be inserted between the uppermost layer in the laminated stack and tunnel barrier layer 16 to provide a CoFeB interface with the tunnel barrier thereby enhancing DRR for MTJ 10.

According to one preferred embodiment, non-magnetic spacer 16 is a tunnel barrier layer having a metal oxide composition that is one of MgO, TiOx, AlTiO, MgZnO, Al₂O₃, ZnO, ZrOx, HfOx, or MgTaO. More preferably, MgO is selected as the tunnel barrier layer because MgO provides the highest magnetoresistive ratio (DRR), especially when sandwiched between two CoFeB layers, for example. In other embodiments, the non-magnetic spacer may be a so-called CCP layer wherein conducting current paths made of a metal are formed in a metal oxide matrix.