Study of the magnetic properties of Ni/Ag superlattice

Abstract

Thin multilayer films of alternating ultrathin Ni and Ag layers (L(Ni) = 11, 15, 30 Å, bulk and L(Ag) = 50 Å) have been prepared by evaporation in ultrahigh vacuum under controlled conditions and have been studied by the magnetic measurements. The critical temperature T C is studied as a function of the surface exchange interaction (J S). The dependence of T C on the thickness L of the film has been investigated. A critical value of the surface exchange interaction in the film, above which the surface magnetism appears, is obtained. The shift of the critical temperature T C(L) from the bulk value [TC(∞)/T C(L)-1] can be described by a power law L -λ, where λ = 1/v b is the inverse of the correlation length's exponent. The effective critical exponent associated with the magnetization M(β) is deduced for different thicknesses of Ni layers, and the thickness L(Ag) was being kept constant at 50 Å. © The Author(s) 2010.