Strong antiferromagnetic interlayer exchange coupling in [Co/Pt]_6/Ru/[Co/Pt]_4 structures with perpendicular magnetic anisotropy

摘要

The interlayer exchange coupling properties of perpendicular synthetic antiferromagnetic (p-SAF) structure were investigated in this work by varying the Ru spacer thickness (t(Ru)). We observed an oscillatory decay of interlayer exchange coupling field (H-ex) and coupling strength (J(ex)) with a period of about 0.6 nm. The greatest values of H-ex and J(ex) are 13.2 kOe and 1.77 erg/cm(2) at the 1st peak, respectively. The H-ex decreases significantly to about 6.2 kOe with the increase of t(Ru) from 0.44 nm at the 1st peak to 1.03 nm at the 2nd peak. The effect of post-annealing temperature on the H ex was also investigated. The H ex decreases with the increase of annealing temperature. Furthermore, after annealing at 380 degrees C, the J(ex) value remains as high as 0.94 erg/cm(2) at the 1st peak. Our results represent a candidate for spin-transfer torque magnetic random-access memory (STT-MRAM).