Figure 3: Experimental and simulated critical current variation with in-plane magnetic field.

(a) Critical current versus in-plane magnetic field of a Nb/Cu(5 nm)/Py(1.5 nm)/Cu(5 nm)/Co(5.5 nm)/Cu(5 nm)/Py(1.5 nm)/Cu(5 nm)/Nb junction measured at 4.2 K. The red dotted line in a representing the shift in the zero critical current line due to the finite non-zero voltage used to measure the critical current (see Methods for details). The inset shows the current–voltage characteristic of the junction recorded at −40 mT to verify the absence of critical current. (b) Simulated I_C(H) pattern (green and brown curves) showing the combined effect of inhomogeneous magnetic state giving rise to a spin-polarized supercurrent and the effect of the flux taking into account the magnetic inhomogeneity. The green curve takes into account the actual sign of sin φ₁ sin φ₂ and thus accounts for the sign of the supercurrent depending on local 0 or π states, whereas the brown curve only takes the modulus of sin φ₁ sin φ₂. Inset shows the variation of the maximum supercurrent (I_C0) in the junction and the combined effect of flux arising from an inhomogeneous barrier moment and the applied field on the critical current as a function of an in-plane applied magnetic field. (c, i–v) The plan views of the magnetic states (from OOMMF simulations) for outer Py and central Co layers are shown with the corresponding magnetic fields as indicated below. The states corresponding to the field values shown are also marked in b.