Magnetostatically driven domain replication in Ni/Co based perpendicular pseudo-spin-valves

The effect of ferromagnetic layer thickness on the temperature-dependent stray-field-induced coupling mechanism is investigated in perpendicular pseudo-spin-valves based on [Ni/Co](5)/ Cu/Co-[Ni/Co](n) (n = 2, 3, 4, and 5). Experimental observations show that as n increases from 2 to 4, the difference in coercivity and anisotropy between the two ([Ni/Co](5) or bottom-layer, and [Ni/Co](n) or top-layer) layers increases and the room temperature coupling strength decreases. The coupling then increases for n = 5, as the coercivity difference shrinks and anisotropy decreases. At reduced temperature, the layers start to decouple at a temperature, which increases with n from 2 to 4 and decreases for n = 5 via a stray-field domain-replication mechanism. Our results are useful to control the coupling in pseudo-spin-valves for practical applications in magnetoresistive devices.