Magnetization reversal and anisotropy in CoO/permalloy/Cu/permalloy/NiO layered structures

This work presents results on the temperature dependence of the hysteretic processes of glass /CoO/permalloy/Cu/permalloy/NiO layered structures. The antiferromagnetic behavior of both oxides below their different blocking te mperatures leads to the apparition of unidirectional anisotropy and enhance ment of coercivity in the permalloy layers. The magnetization reversal is i nfluenced by the exchange coupling between the permalloy layers, which is c ontrolled by the Cu thickness. Both ferromagnetic layers remain uncoupled f or 7.5 nm Cu thickness and are coupled for 1.5 nm. The hysteresis loops mea sured along different directions of the samples at room temperature point o ut the different features in the magnetization processes of systems with un iaxial and/or unidirectional anisotropies. (C) 2001 Elsevier Science B.V. A ll rights reserved.