Dependency of tunneling magnetoresistance ratio on Pt seed-layer thickness for double MgO perpendicular magnetic tunneling junction spin-valves with a top CoFeB free layer ex-situ annealed at 400 °C.

For the double MgO based perpendicular magnetic tunneling junction (p-MTJ) spin-valves with a top CoFeB free layer ex situ annealed at 400 °C, the tunneling-magnetoresistance ratio (TMR) strongly depended on the platinum (Pt) seed layer thickness (t ): it peaked (∼134%) at a specific t (3.3 nm). The TMR ratio was initially and slightly increased from 113%-134% by the enhancement of the magnetic moment of the CoFeB pinned layer when t increased from 2.

Influence of face-centered-cubic texturing of Co2Fe6B2 pinned layer on tunneling magnetoresistance ratio decrease in Co2Fe6B2/MgO-based p-MTJ spin valves stacked with a [Co/Pd](n)-SyAF layer.

The TMR ratio of Co2Fe6B2/MgO-based p-MTJ spin valves stacked with a [Co/Pd]n-SyAF layer decreased rapidly when the ex situ magnetic annealing temperature (Tex) was increased from 275 to 325 °C, and this decrease was associated with degradation of the Co2Fe6B2 pinned layer rather than the Co2Fe6B2 free layer. At a Tex above 325 °C the amorphous Co2Fe6B2 pinned layer was transformed into a face-centered-cubic (fcc) crystalline layer textured from [Co/Pd]n-SyAF, abruptly reducing the Δ1 coherence tunneling of perpendicular-spin-torque electrons between the (100) MgO tunneling barrier and the fcc Co2Fe6B2 pinned layer.

The dependency of tunnel magnetoresistance ratio on nanoscale thicknesses of Co2Fe6B2 free and pinned layers for Co2Fe6B2/MgO-based perpendicular-magnetic-tunnel-junctions.

The tunnel magnetoresistance (TMR) ratio of a cobalt-iron-boron (CoFeB)-based perpendicular-magnetic-tunnel-junction (p-MTJ) spin valve is extremely sensitive to both nanoscale Co2Fe6B2 free- and pinned-layer thicknesses. The TMR ratio peaks at a Co2Fe6B2 free-layer thickness of 1.05 nm, while it peaks at a Co2Fe6B2 pinned-layer thickness of 1.