Absence of reversed magnetic anisotropy in (111) Cu/Ni/Cu structures

Abstract

The previously observed complete reversal in magnetic anisotropy for thin (100) Ni layers in the Cu/Ni/Cu structures is revisited to find the crucial information on the generality of such an observation for other orientations. (100) and (111) oriented Cu/Ni/Cu structures with different Ni thickness, 25-500 Å, and fixed Cu thickness, 1000 Å, are compared for their changes of ferromagnetic properties with Ni thickness. A complete reversal in anisotropy between the in-plane and normal-to-plane magnetization curves is seen for the (100) Cu/Ni/Cu structures with Ni layers thinner than 100 Å, as previously observed. A squared hysteresis loop is seen for the normal-to-plane curve, with no loop for the in-plane curve, in these structures. The (111) structures with identical thicknesses, however, show no sign of reversal in anisotropy over the Ni thickness explored. A hysteresis loop remains seen for the in-plane magnetization of the (111) structures down to a Ni thickness of 50 Å, with no loop for the normal-to-plane one. At a Ni thickness of 25 Å, no loop is seen for both curves. The role of orientation and the effect of lattice deformation, are discussed among these structures and Cu-Ni superlattices. © 1991.