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 temperatures leads to the apparition of unidirectional anisotropy and enhancement of coercivity in the permalloy layers. The magnetization reversal is influenced by the exchange coupling between the permalloy layers, which is controlled by the Cu thickness. Both ferromagnetic layers remain uncoupled for 7.5 nm Cu thickness and are coupled for 1.5 nm. The hysteresis loops measured along different directions of the samples at room temperature point out the different features in the magnetization processes of systems with uniaxial and/or unidirectional anisotropies