Hybrid magnetic anisotropy [Co/Ni]15/Cu/[Co/Pt]4 spin-valves

Thin film multilayer heterostructures consisting of two magnetically coupled stacks, one with in-plane and the second one with out-of-plane magnetic anisotropies, are very promising hybrid magnetic anisotropy materials for spintronics. Here we present results on magnetic and magnetoresistance properties of [Co/Ni]15 (in-plane)/Cu/[Co/Pt]4 (out-of-plane) spin-valves with hybrid magnetic anisotropy. We demonstrate that the saturation field and magnetoresistance depend on the thickness of the copper interlayer (tCu) and they have peak values at tCu = 2.5 nm, where the antiferromagnetic coupling is maximum. We reveal that an indirect exchange coupling between [Co/Ni]n and [Co/Pt]m stacks decreases the magnetization switching fields making these systems suitable for low-field sensor, spin torque oscillator and bit patterned media applications.