Magnetoresistive Properties of CoFe/Cu/CoFe/Dy Pseudo Spin Valves under Conditions of Interdiffusion of Dysprosium and CoFe Ferromagnetic Alloy Layers

Abstract

Pseudo spin valve nanostructures, which comprise a dysprosium layer and exhibit giant magnetoresistance, are prepared by magnetron sputtering. The field dependences of magnetoresistance of the as-prepared nanostructures and nanostructures subjected to annealing and prolonged aging at room temperature were measured in a 83–333 K temperature range. Changes in the shape of magnetoresistance curves are used to identify changes in the magnetic state of the nanostructure. The microstructure of the nanostructures has been studied. Changes in the microstructure and magnetoresistive properties of pseudo spin valves were found, which are caused by annealing and storage. The results are interpreted on the assumption of the formation of Dy–Co–Fe ferromagnetic alloy at the CoFe/Dy interface.