On the magnetic ordering in interleaved Fe(3 ML)/V(y ML)/Fe(2 ML)/V(y ML) superlattices

The magnetic properties of superlattice films with alternating Fe thicknesses, Fe(3 ML)/V(y ML)/Fe(2 ML)/V(y ML) with 4 ≤ y ≤ 15, prepared by dc magnetron sputtering on MgO(001) substrates are studied by superconducting quantum interference device measurements. By investigating the basic magnetic observables of the films: the transition temperature Tc, the magnetic remanence Mr, and the saturation field Hs, which change in a correlated manner as a function of the vanadium spacer thickness, y, we find antiferromagnetic (AFM) coupling in Fe(3 ML)/V(y ML)/Fe(2 ML)/V(y ML) for 9 < y < 11. The derived values of the spin wave parameter B and the ground state magnetic moment ms0 also change synchronously with Tc, Mr, and Hs. The peak of the AFM coupling energy per unit area, I, is estimated to be ∼ 0.06 mJ m-2 using the Hs versus y dependence