Enhanced interfacial magnetic coupling of Gd/Fe multilayers

The spatial extent zeta (AFM) and strength J(AFM) of the antiferromagnetic (AFM) exchange coupling at buried Gd/Fe interfaces in ferrimagnetic [Gd(50 Angstrom )Fe(15, 35 Angstrom)](15) sputtered multilayers is obtained from combined x-ray resonance magnetic reflectivity and magnetic circular dichroism measurements. zeta (AFM), is 4.1(7) Angstrom or similar to1-2 interatomic distances in bulk Gd and Fe; J(AFM) is 1050(90) K, comparable to the ferromagnetic exchange in bulk Fe.